I finally got around to cleaning up the script and writing a README for it, which I put into a repository over at Codeberg:

https://codeberg.org/jim-p/otgimagemgr

I have used this script with success on Raspberry Pi Zero 2W devices, along with an Orange Pi One and an Orange Pi Lite.

I know there are other ways to do similar things, like Plop Boot Manager, but I prefer this way as it works more closely to using the hardware directly, which makes a difference for some of my use cases.

Additionally, this functionality can be turned on/off remotely without physically unplugging it, making it superior in cases where you cannot (or do not want to) leave the boot media in place. If the target device has a serial console, it can all be handled remotely without hands on the hardware.

Another bonus is that you can keep an image in place to act like a writable thumb drive. While the script doesn’t facilitate this, you can also mount that image locally on the Pi itself as a way to transfer files to/from a host without using network connectivity.

Hopefully someone else finds this useful!

I also have a couple devices running FreeBSD that also can serve disk images over OTG, but they operate very differently, and this script cannot work. However, it’s not nearly as complicated to setup as Linux so I have not bothered to automate the process there. That’s a post for another day, however.

Why don’t I use tmux? Well, I’ve been using GNU Screen for 30 years, I like it, I’m used to it, and it can talk directly to serial ports without involving any extra software.

Old Syntax Example

In my previous post about using GNU screen as a part of a Raspberry Pi serial console server, I included a status bar example which is actually the default FreeBSD status bar they include in /usr/local/etc/screenrc:

hardstatus alwayslastline
hardstatus string '%{gk}[%{G}%H%{g}][%= %{wk}%?%-Lw%?%{=b kR}(%{W}%n*%f %t%?(%u)%?%{=b kR})%{= kw}%?%+Lw%?%?%= %{g}]%{=b C}[%m/%d/%y %C %A]%{W}'

This example is the older Screen 4.x color syntax, which specifies colors using letters, and is now deprecated in Screen 5.x.

Color Code Changes

In the new style, colors are coded as 0-15 for basic ANSI, 0-255 for 256 color mode, and for truecolor terminals it can either use a hexadecimal code starting with x, or HTML notation as hexadecimal digits following a #. Foreground and background are specified by separating them with a semicolon.

The screen(1) man page says that 3-character HTML style notation should also work, but in my brief testing it did not produce the expected results.

Color Order Changes

In addition to the change in color format, the order also changed. In the old style the background color was first, then foreground. In the new style it is foreground then background. While that is a much better choice logically, it adds to the confusion when updating.

New Syntax Example

Fortunately, the fine folks at FreeBSD have updated their default screenrc to have the new syntax, so we can use that as the new example:

hardstatus alwayslastline
hardstatus string '%{2;0}[%{+b10;0}%H%{-}][%= %{7;0}%?%-Lw%?%{+9;0}(%{+15;0}%n%f %t%?(%u)%?%{-})%{-} ^H%?%+Lw%?%= %{-}]%{+b14;0}[%m/%d/%y %c]%{-}%{-}'

I tried converting my slightly modified version to the new syntax and ended up with nearly the same line, but theirs works better. See my note at the end of this post about the bug I hit, which the FreeBSD example works around.

If your terminal supports truecolor, you can enable support for that in screen and use the HTML style color syntax instead:

truecolor on
hardstatus alwayslastline
hardstatus string '%{#008000;#000000}[%{+b#00FF00;#000000}%H%{-}][%= %{#C0C0C0;#000000}%?%-Lw%?%{+#FF0000;#000000}(%{+b#FFFFFF;#000000}%n%f %t%?(%u)%?%{-})%{-} ^H%?%+Lw%?%= %{-}]%{+b#00FFFF;#000000}[%m/%d/%y %C %A]%{-}%{-}'

Unfortunately, the new syntax and old syntax are incompatible both ways, so you can’t form a status line that works on both GNU Screen 4.x and 5.x. You also don’t appear to be able to form a status line that falls back to 16 or 256 colors if the terminal doesn’t support truecolor. So you might want to keep several variations on hand to use in appropriate circumstances.

Padding Bug

When converting my status line I hit a bug where if you have padding on both the left and right sides, the color of the last window entry in the list didn’t have color applied properly.

Using a smaller example, the background color was being applied way to the left.

Small example that demonstrates the bug:

hardstatus alwayslastline 'Left%=%-Lw%{7;4}%n%f %t%{-}%+Lw%=Right'

Using the FreeBSD default line as an example, I noticed they had a space and a backspace after the active window, which appears to work around the problem:

hardstatus alwayslastline 'Left%= %-Lw%{7;4}%n%f %t%{-} ^H%+Lw%= Right'

I submitted a bug report upstream, but since there is a workaround it’s fairly low priority.

In a previous post I discussed fluorescent inks that react to ultraviolet (UV) light. Part of getting the best results out of those inks is using them on paper that does not react to UV light sources itself. This gives fluorescent inks the best chance of standing out and their glow being visible under UV light.

Paper can be UV reactive for various reasons, such as from the processes manufacturers use to make the paper bright white, like bleaching. As a consequence, a good general guideline is to look for “ivory” or “cream” papers and avoid bright white paper.

There is a surprising amount of variation between brands and even different types of paper from the same brand. This post covers many of the different types of paper I have been able to try, along with photos of each under UV light. It’s more of a relative comparison and not exactly rigorously tested or scientific.

Safety

Before going any further, UV light has safety concerns that merit caution.

In this post, unless otherwise specified, “UV” refers to the UV-A portion of the ultraviolet spectrum around 315-400nm, specifically closer to 365nm as that is where most of the lights being discussed peak.

Though this “long wave” UV isn’t as harmful as other portions of the UV spectrum, it can still be harmful with prolonged skin exposure and any amount of eye exposure. Wear eye protection when using UV lights, and limit exposure where possible.

Many polycarbonate (PC) glasses block UV-A light. This includes safety glasses, and some others such as reading glasses or even eyeglasses, depending on how the lenses were made. Since these are very common, chances are high that many people already have some form of viable eye protection nearby. Try shining a UV light through glasses at a UV reactive object, if the object doesn’t react to the light through the glasses, but does when the glasses are not in front of the light, then the glasses can block UV light.

Any use of UV lights is at your own risk. Protect your eyes!

Light Sources

To get the best effect with UV reactive materials, a UV light should only emit light in the UV-A range. This can be quite difficult in practice as many lights labeled as “UV” put out a much wider range and appear to give things a purple hue in addition to whichever portion of the UV spectrum they are supposed to emit.

I’ll have a separate post about a selection of lights I have used and tested. Generally speaking, try to find a UV light source with a ZWB2 filter. A ZWB2 filter blocks the visible portion of the color spectrum, so only UV-A light near 365nm can pass. This allows UV reactive materials to fluoresce and shine while minimizing discoloration by non-UV wavelengths emitted by the light.

Most lights I use have ZWB2 filters, including an Emisar D4v2 UV Mule, Emisar D2 with a UV channel, and Lumintop Tool AA UV.

Methodology

I used the same pens and fluorescent inks on each paper with some different nib types and widths:

• Tono & Lims Antares in a TWSBI ECO 1.1 Stub
• Tono & Lims Regulus in a Platinum Preppy F03
• Tono & Lims E=mc² in a Platinum Preppy F03
• Pennonia Napnyugta/Sunset in a Jinhao 20 EF
• Tramol Turritopsis Nutricula invisible ink in a TWSBI ECO 1.1 Stub

To keep things on a level playing field, I took consistent photographs of each paper. I setup a camera on a tripod and put a UV light in a clamp arm. The camera photos were all taken on a Canon EOS Rebel SL2, set to manual focus, f/5.6, 1/200 sec exposure, ISO 6400. As the settings are identical for all of the camera photos, these photos allow for direct comparison. The photos can be used to determine the result between each paper type with respect to how bright the inks and paper are, even if they don’t look the best.

I also took photos of each paper on a phone camera. While these are not as useful for direct comparison, they give a better impression of how the paper and ink combinations appear to the eye.

Each paper type listed in this post will include both the camera photo and the phone photo.

Paper Types

I have ranked the papers I was able to test from most reactive (worst) to least reactive (best).

12 - Notsu Notepad

I have a few of these Notsu tear-off notepads around because they are a convenient size, dot grid, thick paper, and reasonable friendly for fountain pens. They’re also not terribly expensive so I don’t mind leaving them around the house for general non-fountain-pen use.

Unfortunately, the paper reacts to UV light more than any other paper I have. It’s extraordinarily bright under UV and drowns out the ink. It’s still good paper for other uses, but not with UV ink.

Antares and Sunset are easily readable, and Antares is visibly glowing, but the rest are barely visible. The invisible ink is somewhat readable, but not easy to see against the glowing background.

11 - Clairefontaine Triomphe - Vellum

This Clairefontaine Triomphe notepad has lined tear-off sheets of vellum paper. Clairefontaine has other types of paper as well, one of which is in another entry later in this post.

However, while it’s good for general usage, it’s not good for UV inks as it is extraordinarily reactive to UV light.

Like the previous paper, Antares and Sunset are easily readable, and Antares is visibly glowing, but the rest are barely visible. The invisible ink is slightly more legible than on the Notsu.

10 - Endless Recorder Notebook (Regalia paper)

This Endless Recorder Notebook has “Regalia” paper and is grid lined.

While it is fairly reactive, it is not nearly as bad as the two previous papers. The paper glows, but most inks are still quite visible.

In particular, sunset is readable but doesn’t appear to be glowing. It’s not unusable, but I would not recommend it for usage with UV inks.

9 - Maruman Mnemosyne Spiral Notebook

This paper is from a Maruman Mnemosyne spiral-bound notebook. I have A5 and A6 versions of this notebook and they both perform similarly.

The glow of the paper is similar to the Endless Recorder Notebook, but the dot grid doesn’t get in the way as much.

Most of the inks still were sufficiently visible. Sunset still doesn’t appear to be glowing, though.

8 - Sakae TP Iroful notebook (dot grid)

This sheet is from a Sakae TP Iroful A5 notebook with dot grid printing.

Iroful paper is remarkable in various ways, it seems to do things with ink that other papers don’t or can’t. I like using it for pretty much anything fountain pen related.

That said, it is still somewhat reactive to UV. It has slightly less glow than the papers already mentioned, though, so it’s still an improvement.

All of the inks are readable and all but Sunset are glowing. Note that Regulus is glowing more green on this paper, while it was more blue on the others.

7 - Sakae TP Iroful loose sheets (blank)

The base paper of blank Iroful loose sheets is the same as the dot grid notebook, and I almost didn’t test it, but it turned out to be another slight improvement.

Without the dot grid (or whatever process they use to print the dot grid), it reacts a tiny bit less.

The background being smooth and empty also helps it interfere less with the ink.

6 - Clairefontaine Triomphe - Velvety Ivory

This sheet of paper is from a Clairefontaine Triomphe notebook with their “velvety ivory” paper.

This variation isn’t as white as the vellum, is much better in terms of UV reaction, and has significant overall reduction in paper glow from the previous paper.

The paper has a scattered amount of highly reactive fibers, however, which looks neat but does make it less effective than it would be otherwise. Still, with the right ink that effect can be desirable.

All of the inks are readable and Sunset finally appears to be glowing, albeit faintly. Regulus is back to Blue again.

5 - Midori MD Cotton tear-off pad

This sheet is from a Midori MD Cotton tear-off pad, which is a bit different from typical Midori MD paper.

This paper offers another significant reduction in UV reaction, though there is still a faint glow. There are also some reactive fibers in the mix, but they are sparse.

The inks are all readable and glowing, and stand out much better than the papers mentioned so far.

This is the first paper of the bunch I’d consider recommending, though there are even better options to come.

4 - Paperage Journal Notebook

This sheet is from a Paperage Journal Notebook. It’s fairly inexpensive compared to some of the other options (especially the ones below this point), has a nice hardcover, comes in a variety of colors, and so on. Not bad all around for the price.

The paper has a very low reaction to UV and only a faint glow.

Despite the faint glow, all the inks glow much brighter than the paper. So, even if the conditions are not ideal, it hits a good price/performance balance.

3 - Midori MD Notebook

This sheet is from a Midori MD notebook, and this paper is one of my favorites for regular use. They also make a tear-off note block with the same paper, which is ideal for quick tests, making swatch cards, and so on.

The paper has almost no perceptible reaction to UV, it has barely any glow at all.

The very low reaction and minimal glow really lets fluorescent inks shine!

2 - Life Noble Note

This sheet is from a Life Noble Note notebook, which can be somewhat hard to find.

The paper itself is is darker, but ever so slightly reactive, and there are some very sparse reactive fibers. It balances out to make a fine option, though not one I prefer personally.

All of the inks are glowing brightly, however, and look great.

1 - Tomoe River S Kanso Notebook

This sheet is from a notebook made with Tomoe River S Kanso paper sold by JetPens under their own name. There is some concern about differences in Tomoe River paper between batches when repackaged by different places (e.g. Habonachi), so consider that when purchasing.

The paper has no visible reaction to UV and in my opinion it is the best choice to let fluorescent inks show off. However, it’s also a bit more expensive than the other options and each notebook would need to be checked to ensure it behaves as expected.

As you can probably guess, with no visible glow from the paper, the ink glows brightly and looks fantastic.

Conclusion

The differences are quite stark in the above photo, which has all of the papers I tested from least to most reactive in the numbered order of this post. There is a pretty steep increase in reactivity beyond the top row.

Any of the top three papers are excellent for use with fluorescent inks: Midori MD, Life Noble Note, or Tomoe River S Kanso. Honorable mention to Paperage and Midori MD Cotton.

Personally, I use Midori MD most often because of its consistency, cost, and availability.

I’ve had an interest in ultraviolet (UV) “blacklight” reactive items for many years. They come in many forms, like glow in the dark toys and decorations (LEGO ghosts!), clothing, or even certain rocks. If I can hit something with a UV light and it fluoresces or glows, I get a kick out of it. My current wedding ring even glows! Since I started using fountain pens more in the past year, I was eager to try out UV reactive fountain pen ink, but finding a suitable ink was a challenge. Not only were there not many choices, but some were not viable and others were difficult to obtain.

Safety

Before going any further, UV light has safety concerns that merit caution.

In this post, unless otherwise specified, “UV” refers to the UV-A portion of the ultraviolet spectrum around 315-400nm, specifically closer to 365nm as that is where most of the lights being discussed peak.

Though this “long wave” UV isn’t as harmful as other portions of the UV spectrum, it can still be harmful with prolonged skin exposure and any amount of eye exposure. Wear eye protection when using UV lights, and limit exposure where possible.

Many polycarbonate (PC) glasses block UV-A light. This includes safety glasses, and some others such as reading glasses or even eyeglasses, depending on how the lenses were made. Since these are very common, chances are high that many people already have some form of viable eye protection nearby. Try shining a UV light through glasses at a UV reactive object, if the object doesn’t react to the light through the glasses, but does when the glasses are not in front of the light, then the glasses can block UV light.

Any use of UV lights is at your own risk. Protect your eyes!

Turritopsis Nutricula

I found a couple UV reactive inks, but after reading several reviews and related material around the Internet, I ultimately decided that Turritopsis Nutricula by Tramol was the ink I wanted to try. I bought two 18ml bottles on AliExpress for about $5 each, which is a decent price for specialty ink. Even before getting to the ink, I liked the Jellyfish on the label. Shining a UV light on the bottle made it glow pretty brightly, which made me eager to get the ink in a pen to try it out.

Though I am aware of other alternative invisible UV fountain pen inks, I opted not to buy them for various reasons.

Initially I put the ink into a pen I purchased specifically for this purpose, a Penbbs 494 with an EF nib. I used that pen as it was relatively inexpensive and if the ink didn’t behave well, it wouldn’t be a significant loss. Eventually after using the ink for a while and seeing how well it worked, I also put the ink in a TWSBI ECO Glow Green pen with a stub nib.

Rhymes with Blinvisible

Turritopsis Nutricula is UV reactive “invisible” ink. Without UV light, the ink is not visible at all on paper. In certain cases you might see a dent in the paper from the nib of the pen, or a hint of clear wet liquid before it dries, but otherwise it looks as if nothing is on the paper. Shine a UV light on the paper and it’s a different story entirely: the ink glows a light blue color so bright it almost looks white!

The results are nothing short of amazing, writing with this ink under UV looks like you’re writing with light! I’ve been extremely impressed by it, especially for the relatively low cost. The results are improved significantly when using it in combination with certain UV lights and specific paper types, but I’ll have more on that later.

Why ask why?

As to the ink’s purpose, there are numerous fun things to do with it: hidden messages, secret additions to notes, sensitive information, drawings that glow or look different under UV and non-UV light, or just for general amusement. It also fits right in around Halloween.

Hurry up and wait

Getting the ink may present a minor challenge, however. I found it on AliExpress under the ink name (Turritopsis Nutricula) but the listing didn’t include the brand name. Search for terms such as uv invisible fountain pen ink and find the bottle matching the picture earlier in this post – it should have an image of a Jellyfish. The ink can sometimes be found on Amazon, but rarely under its actual name, and at a much higher price. Search using the same terms I suggested for AliExpress and you’ll probably find it. The last time I saw on Amazon, it was about $10 for the same bottle.

When ordering from AliExpress, the ink ships from China so it takes a while to arrive. Time isn’t the only factor, however, ink in a glass bottle taking a trip that long has an increased chance of damage in transit. Even buying from Amazon, however, it may still ship from China, so carefully check the listing and confirm how it ships.

Mine arrived after two weeks in transit and the box was crumpled significantly, but the contents were safe and intact.

Other UV Ink Options

There are other UV reactive inks out there, too. There are options that are not invisible ink, and also options that aren’t fountain pens.

Highlighter Inks

While I was searching for the invisible ink I also found several UV reactive highlighter style inks from Banmi on AliExpress for about $4 per 18ml bottle. While these are not invisible, they still glow brightly under UV.

These highlighter style UV inks can be used with thinner nibs for drawing/sketching or in wider nibs as a highlighter in combination with water-resistant inks. I don’t see myself using these as often as the invisible ink but the effect is still decent overall.

I didn’t have a good way to test these as actual highlighters, but some of the more visible colors like red and pink could be good for outline/underline even if not used as typical highlighters.

Rollerball Invisible Inks

There are also non-fountain pen options out there, such as these Sakura Gelly Roll UV Gel Pens – They have a similar invisible ink effect, but in different colors. However, since these are pre-packaged disposables, you are locked into using just those pens. Also, since rollerball pens require more pressure than fountain pens, they are more likely to leave behind a visible trace on paper even if the ink itself is not visible.

Getting the Best Results

For UV reactive ink to work well, there are two major factors that come into play: The paper and the UV light source.

Picking Paper

The ideal paper for UV reactive ink is paper that does not react to UV light. When the paper does not react to UV light, it allows the ink to get the most contrast with the paper and shine brightly. If the paper reacts to UV light and glows, it can diminish or even drown out the glow of the ink.

I have a separate post about all the different paper types I have tested, but among the best ones to use that I have found thus far are Midori MD and Tomoe River S Kanso paper.

Isolating Illumination

To get the best effect with UV reactive materials, a UV light should only emit light in the UV-A range. This can be quite difficult in practice as many lights labeled as “UV” put out a much wider range and appear to give things a purple hue in addition to whichever portion of the UV spectrum they are supposed to emit.

As with the paper, I’ll have a separate post about a selection of lights I have used and tested. Generally speaking, try to find a light source with a ZWB2 filter. A ZWB2 filter blocks the visible portion of the color spectrum, so only UV-A light near 365nm can pass. This allows UV reactive materials to fluoresce and shine while minimizing discoloration by non-UV light.

Most lights I use have ZWB2 filters, including an Emisar D4v2 UV Mule, Emisar D2 with a UV channel, and Lumintop Tool AA UV.

Conclusion

Overall, these inks are fun to work with and are well worth the low cost and moderate effort to obtain. Whatever your purpose for it may be, I highly recommend trying the ink at least once. The paper and UV lights that work best with this ink also have many uses other than UV ink, so they are good to have even for general use.

https://anduril.click/

Recently some lights have started using ATtiny1616 chips with a 3-pin flashing pad interface for firmware updates. Notably, this includes the Wurkkos TS10 and Sofirn SP10 Pro, but possibly covers new revisions of others lights such as the Sofirn LT1, LT1 Mini, SC31 Pro, SP36, and Q8.

This interface is, in some ways, much easier to work with than the previous ones I’ve dealt with. Less pins to worry about lining up, easier to adapt parts on hand, and so on. That said, it does have its drawbacks, such as possibly requiring different software to update and also a new serial interface board since it doesn’t work with USBASP like the other lights.

Supplies

• Serial USB to TTL CH340 Module device

  The one linked specifically works great as-is, so I suggest using that one. There are others out there that may require soldering in a resister or certain diode, but these modules do not need it.

• Jumper wires with Dupont connectors

  The CH340 linked above comes with some wires that have M-F connectors which can help with some parts of this but for most probes you will likely need F-F.

• Flashing kit from Hank (US Source) or another probe with at least three pogo pins in line, such as an HQ ProgKey.

I have used both my HQ ProgKey and Hank’s probe. Both work fine, but the HQ ProgKey can be used on a wide variety of lights thanks to its 4-over-4 layout. I ordered a couple batches of the HQ ProgKey from OshPark and used soldering paste and a reflow plate to attach pogo pins to the ProgKey. For many people that’s probably overkill, but it does work well for updating my non-Hank lights.

Why Update?

Why update? It depends.

Sometimes there are important software bug fixes. For example, the stock TS10 firmware had a couple problems. The aux lights stayed on while the main emitters were on, and it lacked low voltage protection for its single color aux LEDs, so the aux LEDs (especially on high) could drain a battery to dangerously low levels.

There are other reasons to update, such as:

• For new quality of life changes, like the recent changes in lockout behavior (3C from lockout to unlock off instead of just 4C to unlock and turn on). The new TS10 firmware also lowers the moonlight from about 0.1 lumens to 0.01 lumens which is a significant decrease.
• If you have multiple Anduril lights, it’s convenient to have all the lights using the same UI and you don’t have to remember which ones work which way because they had slightly different Anduril versions on them from the OEM.
• Maybe you are like me and geek out on this kind of stuff and like doing it

Wiring up the Probe

If using Hank’s kit, with the four pin side up, use the first three pins left to right:

• Pogo Pin 1: Top row, far right: R / RX+TX
• Pogo Pin 2: Top row, far left: - / GND
• Pogo Pin 3: Top row, second from left: + / 3V3

If using a custom adapter, wire the pins up similarly:

• 1: R / RX+TX
• 2: - / GND
• 3: + / 3V3

On the CH340 device linked above, the RX and TX pins are separate but they come with a jumper. The RX/TX wire needs to connect to both pins, which can be done in a variety of ways. Some people prefer to solder a pin on the jumper, or solder a wire across both, or connect two wires and splice them into a single line midway. Personally, I pushed a pogo pin into a Dupont connector and simply wedged it the opening at the top of the jumper. Pressure from the neighboring wires keeps it in place and it makes a good enough connection for this purpose. A similar trick would likely work with a male Dupont connector end. Soldering is a more reliable and permanent solution, but thus far my workaround has not failed.

Connecting the Probe to the Light

Unscrew the head from the light and look inside. These lights will have three pads and they are hopefully labeled properly as either: R - + / + - R. Align the probe so the pins match the pads.

Install Drivers and Locate the Serial Port

Unfortunately at the moment there isn’t a way to program with these chips from Android, so use a computer with the right drivers.

This could be Linux, Windows, or macOS. Requirements vary by platform.

Plug the USB device in and let the OS detect it and install drivers.

Windows

On Windows:

• Right click the Start/Windows button
• Click Device Manager
• Expand Ports (COM & LPT)

• Locate the port labeled “USB-SERIAL CH340” and note the port listed after

  For example COM7.

If there is a ! and the same port is in the list twice:

• Double click the “USB-SERIAL CH340” device
• Click the Port Settings tab
• Click Advanced
• Change the device to a different (unused) COM port number

Linux

On Linux, the device will be /dev/ttyUSB<id> for example, /dev/ttyUSB0 . If there are multiple devices, the correct device is likely the highest one or one with the newest timestamp.

macOS

On macOS, the device will be /dev/cu.usbserial-<id> , the ID will vary by hardware. If there are multiple devices, the correct device is likely the one with the newest timestamp.

Firmware File

Get the correct firmware file, or compile one.

Do a firmware check on the light (15+ clicks, note each digit it flashes) and compare the date and IDs returned. Last four digits should be the Anduril model ID. This is mostly for reference in case there is a discrepancy between what the light was running before and what is loaded after.

For the Wurkkos TS10 or Sofirn SP10 Pro, check at https://www.ghart.com/blf/firmware/hex_files/sofirn_anduril2/ for the latest revision for the light in question. As of this writing, the newest files for the Wurkkos TS10 is anduril.2022-07-19.wurkkos-ts10.hex, Sofirn SP10 Pro is anduril.2022-07-23.sofirn-sp10-pro.hex – Those are likely to change over time.

For other lights, check http://toykeeper.net/torches/fsm/anduril2/

Running the Update

There are two ways to update currently, with either avrdude or pymcuprog.

avrdude

The recently released avrdude 7.0 now supports updating through these interfaces and avrdude may already be familiar for those updating firmware since it is a common way to update other lights that use USBASP boards.

• Download the latest release
• Extract it using whatever tool is handy (e.g. Windows Explorer, 7-Zip, or other file manager or built-in OS utility
• Copy the firmware file(s) to the same directory as avrdude to make it easier
• Open a command prompt and change to the directory where the contents were extracted

Ping the Device to Ensure Connectivity

The first thing to try is to ping the device to ensure that avrdude can talk to both the CH340 device and the target chip. Replace the serial port in the following command with the port used by the CH340 device:

.\avrdude.exe -p attiny1616 -c serialupdi -P com7 -n

The output should look like this:

avrdude.exe: UPDI link initialization OK
avrdude.exe: Device is in SLEEP mode
avrdude.exe: NVM type 0: 16-bit, page oriented write
avrdude.exe: Entering NVM programming mode
avrdude.exe: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude.exe: Device signature = 0x1e9421 (probably t1616)
avrdude.exe: Leaving NVM programming mode

avrdude.exe done.  Thank you.

If there is an error, most likely the probe was not correctly contacting all of the correct pins. Check and correct the probe placement and try again.

Read the Old Firmware

A good practice is to read the old firmware in case the new firmware has an undesirable behavior. That way it’s possible to reload the previous firmware to get back to the prior state.

.\avrdude.exe -p attiny1616 -c serialupdi -P com7 -Uflash:r:old-firmware.hex

The output should look like this:

avrdude.exe: UPDI link initialization OK
avrdude.exe: Device is in SLEEP mode
avrdude.exe: NVM type 0: 16-bit, page oriented write
avrdude.exe: Entering NVM programming mode
avrdude.exe: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude.exe: Device signature = 0x1e9421 (probably t1616)
avrdude.exe: reading flash memory:

Reading | ################################################## | 100% 4.02s

avrdude.exe: writing output file "old-firmware.hex"
avrdude.exe: Leaving NVM programming mode

avrdude.exe done.  Thank you.

Write the New Firmware

Now it is time to write the new firmware. Replace the filename in the following command with the correct firmware filename.

.\avrdude.exe -p attiny1616 -c serialupdi -P com7 -Uflash:w:anduril.2022-07-19.wurkkos-ts10.hex

The output should look like the following:

avrdude.exe: UPDI link initialization OK
avrdude.exe: Device is in SLEEP mode
avrdude.exe: NVM type 0: 16-bit, page oriented write
avrdude.exe: Entering NVM programming mode
avrdude.exe: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude.exe: Device signature = 0x1e9421 (probably t1616)
avrdude.exe: NOTE: "flash" memory has been specified, an erase cycle will be performed
             To disable this feature, specify the -D option.
avrdude.exe: erasing chip
avrdude.exe: reading input file "anduril.2022-07-19.wurkkos-ts10.hex"
avrdude.exe: input file anduril.2022-07-19.wurkkos-ts10.hex auto detected as Intel Hex
avrdude.exe: writing flash (9562 bytes):

Writing | ################################################## | 100% 3.87s

avrdude.exe: 9562 bytes of flash written
avrdude.exe: verifying flash memory against anduril.2022-07-19.wurkkos-ts10.hex:
avrdude.exe: input file anduril.2022-07-19.wurkkos-ts10.hex auto detected as Intel Hex

Reading | ################################################## | 100% 1.85s

avrdude.exe: 9562 bytes of flash verified
avrdude.exe: Leaving NVM programming mode

avrdude.exe done.  Thank you.

Now that the firmware is written to the light, skip ahead to the section on performing a factory reset.

Python and pymcuprog

If avrdude is not a viable choice, install Python and pymcuprog.

On Windows, there are two main ways to get Python:

1. Use the installer from Python
2. Install from the Microsoft Store

After installing python, open a command prompt and install pymcuprog by running pip install pymcuprog

Fix Python Path

There may be some quirks getting the paths right for pymcuprog if Python was installed from the Microsoft Store, since the location for the packages is not in the path by default.

Try running pymcuprog from a terminal, PowerShell, or command prompt, if it prints its usage output, then it’s OK to proceed. Otherwise, check and correct the path or python issues.

In Explorer, first locate the correct folder. It will be something similar to C:\Users\<name>\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_<id>\LocalCache\local-packages\Python39\Scripts – Copy that full path.

The correct path will also be found in the output of python -c "import sys; print('\n'.join(sys.path))" it will be the entry similar to the path mentioned previously.

• Right click on the Start/Windows button
• Click System
• Click Advanced System Settings
• Click Environment Variables
• Find the entry for Path in the User variables section and select it
• Click Edit
• Add the path to the list (paste it in or type it out)
• Click OK, then OK again to close the Environment Variables window
• Click OK one more time to close System Properties

Ping the Device to Ensure Connectivity

The first thing to try is to ping the device to ensure that pymcuprog can talk to both the CH340 device and the target chip. Replace the serial port in the following command with the port used by the CH340 device:

First, try a ping to see if the device responds to a probe:

pymcuprog ping -d attiny1616 -t uart -u com7

The output should look like the following if it’s successful:

Connecting to SerialUPDI
Pinging device...
Ping response: 1E9421
Done.

If there is an error, most likely the probe was not correctly contacting all of the correct pins. Check and correct the probe placement and try again.

Erase the Firmware

Unlike avrdude, pymcuprog does not automatically erase before writing, so do a manual erase:

pymcuprog erase -d attiny1616 -t uart -u com7

The output should look like the following:

Connecting to SerialUPDI
Pinging device...
Ping response: 1E9421
Chip/Bulk erase:
- Memory type eeprom is conditionally erased (depending upon EESAVE fuse setting)
- Memory type flash is always erased
- Memory type lockbits is always erased
Erased.
Done.

Write the Firmware

Change to the directory where the firmware file was downloaded, for example: cd ~\Downloads

Now write the firmware file. Replace the filename with the correct firmware filename that matches the light.

pymcuprog write -d attiny1616 -t uart -u com7 --verify -f anduril.2022-07-19.wurkkos-ts10.hex

The output should look like the following:

Connecting to SerialUPDI
Pinging device...
Ping response: 1E9421
Writing from hex file...
Writing flash...
Verifying flash...
OK
Done.

Factory Reset

After writing the firmware, it’s a good idea to do a factory reset. Hold in the power button while reassembling the light and let go of the button when the light goes out.

On some tail switch lights it helps to fully tighten the tube first, then back it off enough that the aux lights (or main emitter) goes out, then hold the button while twisting it back fully closed.

See Also

This post was based in part on information from the following threads:

• https://www.reddit.com/r/flashlight/comments/u8t6x2/how_to_flash_firmware_on_the_sp10_pro_photos_at/
• https://budgetlightforum.com/comment/1873274#comment-1873274

I have tried several different tactics over the years but the best solution I’ve found so far is to use a Raspberry Pi as a dedicated serial console multiplexer (MUX). The title seemed fitting as it takes multiple inputs (serial consoles) and manages a single output (screen) though the user controls the active input in this case.

Supplies

• Raspberry Pi (or equivalent)

  Though this post is geared toward using a Raspberry Pi with Raspbian as a serial console server, many of the techniques used are general and could be adapted to a variety of platforms.

• USB serial hub with lots of ports

  Like this 13-port USB 2.0 hub. Linux doesn’t seem to get along with lots of USB 3.0 ports and there isn’t any compelling reason to use USB 3.0 for serial consoles anyhow.

• USB serial devices

  Varies by device, some have USB consoles, some have serial ports with 9-pin or RJ45 connectors. Some may require null modem adapters. This is mostly beyond the scope of what I’m trying to cover here. I’m going to assume you can already talk to the devices with USB serial in some way.

  Speaking of USB serial, I like these USB serial adapters for devices with regular non-USB serial ports.

• GNU screen

  GNU screen is capable of talking to serial ports directly, so there is no need to use a separate terminal emulator program such as minicom. Though if you prefer to use a different terminal program in each screen or maybe using tmux, similar tactics should work there, too.

Setup the hardware

Setting up the Pi is out of scope here, I’m going to assume you have a working pi connected to your network.

Using a wired connection is best for real-time interactive work in SSH, but depending on your AP and wireless setup it may still work OK that way.

Connect all of the USB serial devices to the hub and connect the hub to the Pi. To ensure things are probed in the correct and expected order, rebooting the Pi is a useful measure at this point.

From here on, everything is done over SSH connected to the Pi. Use the SSH program of your choice (e.g. OpenSSH, SecureCRT, PuTTY).

Map the serial ports to consistent names

Before setting up the consoles let’s take the time to map each port to a consistent and useful name. Rather than having them numbered, we can set it up so that each port is labeled after the device. This makes keeping the screen names and purposes easier to manage over time. If you are lucky and each one has a unique set of properties, then it won’t even matter which order or ports they plug into or what order they probe in.

Gather device attributes

Look at the connected USB ports:

$ ls -l /dev/ttyUSB*
crw-rw---- 1 root dialout 188,  0 Mar 29 11:36 /dev/ttyUSB0
crw-rw---- 1 root dialout 188,  1 Mar 29 11:42 /dev/ttyUSB1
crw-rw---- 1 root dialout 188,  2 Mar 29 11:53 /dev/ttyUSB2
crw-rw---- 1 root dialout 188,  3 Mar 14 16:08 /dev/ttyUSB3
crw-rw---- 1 root dialout 188,  4 Mar 11 14:04 /dev/ttyUSB4

For each of these, go through the device information and find useful and unique properties which identify a given device. This will give us enough information to craft udev rules to setup the port names. The command probes the entire stack to reach the device, but the one you are interested in is usually a few entries into the output and will look similar to what is shown below.

Replace x in the command with the device number, and repeat the command for each ttyUSB device.

$ sudo udevadm info --name=/dev/ttyUSBx --attribute-walk
[...]
  looking at parent device '/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.1/1-1.1.3/1-1.1.3.2':
[...]
    KERNELS=="1-1.1.3.2"
    ATTRS{manufacturer}=="Silicon Labs"
    ATTRS{idProduct}=="ea60"
    ATTRS{devpath}=="1.1.3.2"
[...]
    ATTRS{serial}=="xxxxxx01"
[...]
    ATTRS{idVendor}=="10c4"

This is an ideal case. The device has a unique vendor ID (idVendor), product ID (idProduct), and serial number (serial). Not every device will have a serial number and multiple devices may even have the same serial number, which complicates matters.

The trickier cases may have to rely on the device path (devpath) which means they have to remain plugged into the same USB port.

Setup udev rules

Create or edit /etc/udev/rules.d/99-usb-serial.rules and add rules based on the attributes for each device along with its name.

$ sudo vi /etc/udev/rules.d/99-usb-serial.rules

# These two devices are similar but have unique serial numbers.
SUBSYSTEM=="tty", \
	ATTRS{idVendor}=="10c4", \
	ATTRS{idProduct}=="ea60", \
	ATTRS{serial}=="xxxxxx01", \
	SYMLINK+="serial_edge"
SUBSYSTEM=="tty", \
	ATTRS{idVendor}=="10c4", \
	ATTRS{idProduct}=="ea60", \
	ATTRS{serial}=="xxxxxx02", \
	SYMLINK+="serial_server"

# These two devices don't have a serial number,
# so we have to use the device path
SUBSYSTEM=="tty", \
	ATTRS{idVendor}=="067b", \
	ATTRS{idProduct}=="2303", \
	ATTRS{devpath}=="1.1.3.7.4", \
	SYMLINK+="serial_switch1"
SUBSYSTEM=="tty", \
	ATTRS{idVendor}=="067b", \
	ATTRS{idProduct}=="2303", \
	ATTRS{devpath}=="1.1.3.7.6", \
	SYMLINK+="serial_switch2"

# This device has a unique vendor and product ID, but use the serial
# number anyhow in case a similar device is added in the future.
SUBSYSTEM=="tty", \
	ATTRS{idVendor}=="0403", \
	ATTRS{idProduct}=="6001", \
	ATTRS{serial}=="xxxxxx03", \
	SYMLINK+="serial_adapter"

Reload and test

Now reload the rules and re-trigger the device detection:

$ sudo udevadm control --reload-rules
$ sudo udevadm trigger --attr-match=subsystem=tty

Now look at the mapped devices with our nice names:

$ ls -ld /dev/serial*
drwxr-xr-x 4 root root 80 Oct 24 15:09 /dev/serial
lrwxrwxrwx 1 root root  7 Oct 24 15:09 /dev/serial1 -> ttyAMA0
lrwxrwxrwx 1 root root  7 Oct 24 15:09 /dev/serial_edge -> ttyUSB2
lrwxrwxrwx 1 root root  7 Oct 24 15:09 /dev/serial_server -> ttyUSB1
lrwxrwxrwx 1 root root  7 Oct 24 15:09 /dev/serial_switch1 -> ttyUSB4
lrwxrwxrwx 1 root root  7 Oct 24 15:09 /dev/serial_switch2 -> ttyUSB3
lrwxrwxrwx 1 root root  7 Oct 24 15:09 /dev/serial_adapter -> ttyUSB0

These will come back on reboot and when devices are unplugged and replugged.

It’s a good idea to reboot at this point to ensure the custom names return as expected.

Check privileges

Ensure that your user can access the serial ports. By default in Raspbian the user is pi and it is a member of the dialout group, and the dialout group has permission to access the ttyUSB* devices. If you use another user, add it to the dialout group.

$ sudo usermod -a -G dialout myuser

Alternately, you can run screen through sudo, but that is typically unnecessary with proper permissions and group memberships.

GNU screen

GNU screen allows a user to run multiple concurrent terminal sessions from a single login session. This is much easier to manage than multiple SSH connections to the same server, with the added benefit that screen can “detach” and leave the terminals connected in the background while the user does other things or even logs out. Later, the user can resume the screen session and it is as if they never left.

Many devices will output critical messages to the serial console and if the user isn’t watching the console when they happen, they can be easily missed. Using screen with a large scrollback buffer means the user can monitor these devices and look back at recent output, search it for specific strings, or even write it out to a file.

Setup screen configuration

Create a configuration file for this dedicated instance of screen:

$ vi .consoles.screenrc 

Add in some useful configuration options along with definitions for each of the serial terminals.

# Handy terminal defaults
termcapinfo xterm ti@:te@
termcapinfo xterm-color ti@:te@
termcap xterm 'is=\E[r\E[m\E[2J\E[H\E[?7h\E[?1;4;6l'
terminfo xterm 'is=\E[r\E[m\E[2J\E[H\E[?7h\E[?1;4;6l'
vbell off

# Status line -- careful the second line is quite long!
hardstatus alwayslastline
hardstatus string '%{gk}[%{G}%H%{g}][%= %{wk}%?%-Lw%?%{=b kR}(%{W}%n*%f %t%?(%u)%?%{=b kR})%{= kw}%?%+Lw%?%?%= %{g}]%{=b C}[%m/%d/%y %C %A]%{W}'

# Misc other defaults
shell -$SHELL
logtstamp on
logtstamp after 1

# No need for the intro screen
startup_message off

# 50000 lines of scrollback per window
defscrollback 50000

# Custom session name
sessionname consoles

# Definitions for each separate screen
screen -t 'Edge'     /dev/serial_edge    115200
screen -t 'Server'   /dev/serial_server  115200
screen -t 'Switch-1' /dev/serial_switch1 115200
screen -t 'Switch-2' /dev/serial_switch2 115200
screen -t 'Adapter'  /dev/serial_adapter 115200

Replace the names, serial devices, and serial port speeds as needed to match your own setup.

The example above works on GNU Screen 4.x, but GNU Screen 5.x changed the syntax for colors. I have a separate post about that, but to keep it short here, use the following status line instead if the host has version 5:

hardstatus alwayslastline
hardstatus string '%{2;0}[%{+b10;0}%H%{-}][%= %{7;0}%?%-Lw%?%{+9;0}(%{+15;0}%n%f %t%?(%u)%?%{-})%{-} ^H%?%+Lw%?%= %{-}]%{+b14;0}[%m/%d/%y %c]%{-}%{-}'

Using GNU screen

Overview

When screen is running it will display a nice status bar with screen numbers and the short names we set above with -t <name>.

Start screen

This command starts screen using our custom configuration file:

$ screen -c ~/.consoles.screenrc

Resume a screen session that is already running

This command resumes our specially named session (consoles) in multi-display mode.

$ screen -S consoles -x

In multi-display mode the user can remain connected to the screen from multiple separate SSH login sessions simultaneously.

Screen commands

The following commands are entered in screen by pressing Ctrl-A (Hold the Ctrl key and tap the a key), then release both and press the next key. For brevity, this will be abbreviated like ^A-d for pressing Ctrl-A then d.

^A-d - Detach

Leaves the session running in the background and returns the user to the shell.

^A-DD (Shift+D twice) - Power detach

Detach and logout in a single step.

^A-a - Toggle next/last screen

Changes between the current screen and the last used screen. If on the first screen, it switches to the next one. Press again to swap back and forth.

^A-<num> - Switch to a specific screen number

Changes to a specific numbered screen 0-9

^A-n - Next screen

Changes to the next screen in order

^A-p - Previous screen

Changes to the previous screen in order

^A-<esc> - Scrollback buffer mode

Enters scrollback history mode. Moving through the buffer depends on the terminal program and settings. It may move with arrow keys, hjkl, or even the mouse scroll wheel. Type ?<string> to search backward, /<string> to search forward. Press Esc again to exit.

^A-\ - Quit

Terminates screen.

^A-: - Screen command prompt

Accepts a text command from the user. For example, to write the contents of the entire scrollback buffer to a file, use :hardcopy -h outfile.txt.

^A-? - Help

Displays a help page with a list of commands and other information.

Finish up

With this in place, you can detach from the screen session and leave it running indefinitely and reattach as needed. This is great for monitoring consoles in case something goes wrong and prints logs or console messages for debugging.

I have an older SP36 BLF from 2020 that was stuck on Anduril 1 while all my other Anduril lights are on Anduril 2, so I finally decided to rectify that. The SP36 was the last Anduril light I had left on Anduril 1 as it was also the most difficult to update.

Hat tip to /u/Wily_Wapiti for their post about updating their own SP36 which gave me some extra guidance and encouraging information.

Since I compulsively write documentation as I go, here are my notes in case anyone else needs them.

Check the version

There are at least three versions of the board around:

• No flashing pads with ATtiny85, which is what I had and what this guide covers
• Flashing pads with ATtiny85
• Flashing pads with ATtiny1616

The models with flashing pads do not need disassembled the way this guide describes and the update procedure would be different, closer to the procedure for updating the LT1.

Before starting, try to do a version check which is 15+ clicks from off. Write down the result. The last four digits will be a model number which can be looked up in the list in the MODELS file and will definitely tell you what it’s running. If the light is running a version of Anduril before the version check was added, it’s likely the older variant similar to this guide or at least likely has an ATtiny85 and not ATtiny1616. If it outputs a date but no 4-digit model code, it’s almost certainly an older model running Anduril 1.

No matter which model the light is, do a test and a read to save the existing firmware to confirm the correct settings before attempting to write.

Supplies

Here are the items I used:

• Flashing kit from Hank or another usbasp board.
• SOIC8 Clip
• Jumper wires with Dupont connectors
• 5mm Allen wrench/hex key
• Duct tape

Getting to the chip

Follow the disassembly procedure at https://budgetlightforum.com/comment/1556068#comment-1556068

That post has pictures and directions, but to save a click, here is the general idea:

• Unscrew the head from the battery tube
• Use needle nose pliers to unscrew the ring retaining the switch
• Remove the ring and rubber switch cover
• Loosen the switch PCB. If it’s glued you may have to use a tool such as a dental pick to pry it free. Mine was loose/unglued (lucky me!)
• Carefully move the switch PCB out of the way but don’t pull too much on the wires.
• Use an Allen wrench, S hook, bent nail, or similar to put downward pressure on the PCB through the switch hole
• You can see through the switch hole and find a bare spot on the board to press. Careful not to dislodge the the wiring and careful not to press the switch wires into the edge of the switch hole as it can damage them.
• Carefully pry, the glue will eventually come free, but watch where the tool will apply pressure.
• With the PCB loose, check to make sure nothing was damaged when removing the board.

I used a 5mm Allen wrench with duct tape covering the end going inside the light. The advantage of the Allen wrench is you can lift up on the handle and use the “elbow” of the wrench against the switch hole as a fulcrum rather than relying on pushing down or hammering. I used a T handle and some socket adapters to get extra leverage and it popped out after some work.

Something softer than tape on the end might have been better, I scraped the PCB a little but it was on an empty spot so not critical.

Wire up the adapter

• Connect a SOIC8 clip to a usbasp board with jumper wires in the right places

  • Use the pin guide below, adapted from a BLF post

    

  • Here are pictures of how I wired up the connection between the usbasp board and the SOIC8 clip:

    

    

  • I used jumper wires with M-F Dupont connectors so I could leave the original leads on my SOIC8 clip and plug into its ribbon cable connector.

• Connect the SOIC8 clip to the correct chip on the PCB, which is the one adjacent to the USB port. There is a divot on the chip marking pin 1, see the pictures and the pinout guide linked above.

As most of these lights can be updated with a SOIC8 clip, after doing this I crafted a more permanent solution using dupont connector blocks. I used a pick to release the single dupont connectors from the wire ends and inserted them into a 2x4 block for the SOIC8 side and a 2x5 block for the usbasp side. This way I can connect what is now effectively a proper ribbon cable in the future without having to remember or look up the pinouts.

Flash the firmware

• Download the firmware hex file for the SP36 from http://toykeeper.net/torches/fsm/anduril2/ or compile a new one.

  • For older SP36 models this will be sofirn-sp36.hex and for newer models it may be sofirn-sp36-t1616.hex
• Copy the sofirn-sp36.hex hex file to the device which will be doing the flashing.
• Connect the usbasp board to whatever you are using the flash the device. In my case this was connected to a phone with a USB OTG adapter.
• I used zflasher AVR
  on Android to perform the update, but there are other ways such as avrdude or similar programs.
• The settings I use for zflasher are:
  • MCU: ATtiny85 (For newer SP36 models this may be ATtiny1616)
  • Memory: Flash
• Read the existing firmware as a separate file (e.g. sp36-old.hex) and save it somewhere safe (optional, but a good idea)
• Write the new firmware to the chip
• Disconnect the SOIC8 clip

Reassemble and finish up

• (Optional) clean up some of the glue residue to make getting the board back in and out easier
• Align the board back up using the USB port and side notches as a guide and gently push it back into place. Odds are it won’t go completely back into place yet.
• Take the batteries out of the tube and screw it back into the head as far as it can go, which should re-seat the board back in place.
• Take the tube back off
• Carefully replace the switch, tucking the wires back inside
• Replace the rubber switch cover and ring
• Tighten the ring back with the needle nose pliers
• Put the batteries back in the tube and factory reset
  • Hold the power button down while tightening the battery tube and keep holding it for ~4 seconds after it gets power. Repeat if necessary.
• Enjoy!

Similar Lights

Slight update, I also have a Sofirn Q8 Pro and BLF LT1. The Q8 Pro does not have flashing pads, the LT1 had pads but they didn’t line up with any adapter I have or could make. But in both cases they only had two phillips head screws holding in the driver board. Remove the screws, the board is loose and it was simple to gently turn it over and use the same SOIC8 clip method on them that worked on the SP36.

Line up the USB port and put the screws back in and reassemble, almost easier than trying to hold an adapter up to the pogo pins while running the update.

Adapted from my post on Reddit.

I recently picked up a Fireflies PL47G2 and didn’t see a flashing how-to out there for it, so I figured I’d write something up. This may work on other Fireflies lights but the PL47G2 is the only one of theirs I have so far.

Required Reading

Before starting, read over the guide for flashing the Sofirn LT1 as the procedure and pin layout is essentially the same. The pin layout on the LT1 is 3 over 3, the PL47G2 is 3 over 4 but one of the pins on the bottom row isn’t used.

Adapt the Hank Flashing Kit

I used the flashing kit from Hank (4 over 2 pinout) so as with the LT1 method it requires adapting the connection to the different pin layout plus some method of connecting an extra pin. I used a multimeter lead with a thin probe on one end and alligator clips on the other, clipped to a similar jumper wire to the ones mentioned in the LT1 thread.

Since writing this originally, I ordered some pogo pins and figured out that they can push fit into a dupont connector, so when I updated the light again, I used that instead of a multimeter probe.

Here are the connectors on my flashing kit with the jumper wires in place. The red wire on the right is going to the multimeter lead.

Firmware File

Grab the latest Anduril build from http://toykeeper.net/torches/fsm/anduril2/

• If the PL47G2 uses emitters other than Nichia 219, download ff-pl47g2.hex

• If the PL47G2 uses Nichia 219 emitters, use either the pl47-219 variant or compile a variation of the pl47g2 firmware with the lower FET PWM levels safe for use with the Nichia emitters.

  The pl47-219 firmware disables low aux levels so it’s not ideal for use on the PL47G2.

  See this commit on my fork of Anduril 2 for an example of the necessary changes to make a custom pl47g2-219 variant. I have also posted a pre-compiled version of the hex file for this variant.

Flashing Software

I used zflasher AVR on Android to perform the update, but there are other ways (like avrdude or similar). I’ll stick to zflasher, though.

Copy the .hex file somewhere on the phone/tablet accessible to the app (e.g. Downloads directory).

Connect the phone/tablet to the flash kit (e.g. using USB C to A Female adapter or OTG cable)

Open the app and set it up as follows:

• MCU: ATtiny85
• Memory: Flash
• Action: Write
• Load the hex file with the firmware

Connect the Pins

Line up pogo pins on the flashing kit such that one pin on the row of 4 is NOT touching anything. Should be like so:

• X is an open pad that is not used
• P is a pad touched by a pogo pin
• N is a pogo pin not touching a pad
• O is an open pad which is where the extra lead goes (multimeter for me)

Test and Update Firmware

In the app, run a test first. If it fails, fix the error and try again. Most likely it wasn’t making contact with all the pins.

If the test succeeds, then write and wait for it to write and verify.

Final Thoughts

Bonus shot of the cobbled together setup to make it happen, with a guest appearance from a D4Sv2 and SC31 Pro working together as a little task light:

HQ ProgKey / Other USB ASP Boards

I ordered a couple batches of these HQ ProgKey PCBs from OshPark to make an adapter I could use for these Fireflies lights.

I used some solder paste to reflow pogo pins and connecting pins onto the adapter and then wired it up to match the pin layout.

I had some trouble initially getting it to work, but as it turns out the problem was the usbasp boards I had purchased from Amazon. The adapter works fine with the board from Hank’s flashing kit, so I’ll keep using that for now.

Adapted from my post on Reddit.

A visit to the Monoprice Select Mini Facebook group or the subreddit shows a surprising (to me, at least) number of people with related problems.A common chorus when discussing the printer is “rewire the bed before you do anything else”. It can manifest as the bed heater not working or the bed temperature readout being incorrect, typically reading 999 or 0.

Since mine had been OK, and I’d owned it less than a month, I figured I had time. I was wrong. After a couple weeks and a non-trivial number of printing hours, the bed wouldn’t preheat. The temperature readout was OK, but it read about room temperature and didn’t move. I canceled the print, went into the printer’s monitor screen and had it preheat the bed. Still nothing. I knew the wires could be the problem so I moved the bed back and forth to see if it would kick in, and it did when I moved it all the way forward. Move the bed back and it stopped. Classic short behavior, so I knew what I was in for. Now I had two choices: One: Send the printer back and get it fixed or repaired, or two: Fix it myself. Option one meant I’d be without the printer for probably a week or two and when it came back it would still have a bad wiring job. Option two means I could have it up and running in a couple days at most, and I could use a better wiring path that wouldn’t be prone to breaking. I opted to fix it myself, but I didn’t have all the parts on hand which is why it took a couple days to fix. While waiting for the parts to arrive I watched some videos on youtube by others who made similar repairs, but I did not want to drill through the case, so I also researched some other options. Once it all arrived it was actually a very straightforward fix, so I documented it all and here it is!

Requirements

I chose to do a no-drill method using a printed side panel to reroute the wires. I do not want to have to deal with the mess of metal shavings that drilling would cause. The directions below assume this method, plus also rewiring the heater connection. Here are the parts I printed to replace the side panel and help run the wires:

• Back panel: https://www.thingiverse.com/thing:2451362
• Front panel: https://www.thingiverse.com/thing:2370329
• Cable brace: https://www.thingiverse.com/thing:1937513 – I used the second version, and mirrored it in Cura so the hole was on the correct side for the side mount cable path

Tools

You’ll need these tools to either reroute the wiring or to repair the bed wires

• Cutters for wire and zip ties
• Philips head screwdriver
• Pliers

If you need to repair the bed wires, you will also need these:

• Wire stripper
• Helping Hand or similar clamp/stand to hold parts in place while soldering
• Multimeter
• Soldering iron
• Soldering tip cleaning sponge (brass or other)
• OR: Instead of all that, you can buy a new bed+wires

Supplies

If you are only rerouting the wires, you’ll want to grab…

• Braided cable sleeve, spiral tube wrap, or similar
• Small zip ties

If you are repairing the bed wires, you’ll also need…

• Solder - Preferably rosin core tin/lead blend for wire/electronics
• 18AWG flexible silicone wire - For the heater wires, if you have to replace the thermistor wires you can use some smaller gauge wire like speaker wire
• Kapton tape - The old tape may be resuable but it’s not worth the hassle
• Heat shrink tubing - 3.5mm diameter should be OK

Rewire Part 1

Getting the wires out

• Use the Move menu to raise the Z axis a few inches up to have clearance to remove the bed
• Remove side panel where SD socket and USB connector are, the wires plug in just behind here.
• Cut the zip ties along the bed wires inside and outside the unit, you might have to remove the bottom panel for easier access, if so, lay the printer down on its side with the removed side panel end facing up.
• Identify the bed wires: there are two pairs of wires, a thicker pair for the bed heater, and a thinner pair for the bed thermistor. Follow them and locate where they run and where they are plugged into the controller board. The heater wires have a larger white connector on the board, the thermistor is a smaller white connector near the open side panel.
• Mark and/or snap a photo of the connectors so you know which side is red and which is black, and where they plug in
• Disconnect the bed wires from inside the unit
• Carefully remove the connector from the end of the heater wires (thicker wires, larger connector) so the wires can be backed out through the grommets. You may not need to do this depending on whether or not you can wiggle the connector through. It is much easier to move the wire without the lump of a connector on it, and it’s not hard to remove the connector, only need something with a fine point to push in the little catch on each wire, like a pin, paperclip, or sharp tweezers.
• Move the wiring back through the grommets so it comes right off the back of the heated bed and not through the body of the printer or the carriage

If you do not need to repair the wires, skip ahead to Rewire part 2.

Repair the wires

• Carefully back out all of the bed leveling screws and set the screws, caps, and springs aside. Don’t lose any pieces!
• At this point the bed is completely separated from the printer so it can be moved it to a better work area, I reattached the connector to the heater wires to keep them together but it will need to be off later to go through the cable sleeve, so it’s up to you.
• Using a multimeter I confirmed my red heater wire had a nasty short. The black wire was fine, but I replaced them both anyhow.
• Mark which connection is positive and which is negative on the bed, and/or take a picture for reference
• Remove the Kapton tape covering the solder connections on the bed
• Carefully desolder the thick heater wires from the bed (outer wires): Hold the soldering iron tip on the solder bead until it reflows and then they come right off
• Cut the connector end of the wires off, keeping a few inches of old wire to splice into later so you can reuse the connector
• Cut two lengths of new 18AWG silicone flexible wire: One red, one black, really the color isn’t important, but it’s good to match.
• Strip a bit off both ends of the new wire and the salvaged connector wires
• Solder one end of each new wire to the bed in the appropriate spot
• Put some 1” Kapton tape back over the solder connections. Preferably use new Kapton tape, not old, but the old may be tacky enough to reuse.
• Put some heat shrink tubing around the wire to be used after splicing
• Mesh or twist the new and salvaged wire ends together
• Solder each pair of wires together to form a strong bond
• Move the heat shrink tubing so it completely covers the solder on each wire with room to spare
• Melt the heat shrink tubing using a high heat source. I used a heat gun, but a lighter or torch works
• If you need to replace the thermistor wires, repeat this procedure again for those, but with appropriate AWG replacement wire
• Replace the bed, using the screws, springs, and caps to reattach it
• You will definitely need to relevel the bed after, but don’t do that yet

Rewire Part 2

Better than new

• Run the bed wires through the hole in the cable brace
• Attach the cable brace on the back of the bed carriage. It needs screws, I used some old PC case screws that fit.
• Slide the wire through some sort of conduit – braided cable sleeve, spiral tube wrap, cable chain, etc. The connector on the heater wires will probably need to be off for it to fit, unless you use spiral wrap which can fit around anything.
• Put a zip tie at either end of the conduit, for example I used braided cable sleeve so I put a zip tie between the bed and the cable brace, and another just before the connectors
• Put the heater wire connector back on if it was removed, and reconnect the heater and thermistor to the main controller board
• Put on the new side panels – If you couldn’t print new side panels because you need the heated bed, just leave the side panel off while you print replacements!
• Relevel the bed and try preheating it

For me, the bed heated right up to 60C where I wanted it, and my prints are back to sticking like I’m used to!

If you choose to do a method involving drilling or if you choose a different side panel configuration, the last few steps may need to change to route the cables through whatever new path is available.