Dead M4 Express

[turbinenreiter]

Hello People,

Has anyone encountered a dead M4 Express before?

* When I plug it in, only the charging LED behaves as it should.
* Double-click to bootloader does nothing - red LED isn't flashing and the NeoPixel isn't doing anything either.
* There is no serial device showing up at all. I didn't do much except taking the board and carrying from my laptop to the other computer and plugging it in there.

Has anyone every killed a Feather with ESD?

I ordered a Segger, so I can re-flash the bootloader, but to me it feels like the chip died :(

[turbinenreiter]

I'm at two dead M4's now :(

[BryonMiller]

I had very similar thing happen to me. Since I could not positively rule out that I did something wrong with power I had to replace it myself. Replacement has been fine.

[turbinenreiter]

Well, I'm at 3 dead boards now and I'm sure I didn't kill any of them, except the last one, where I erased the flash with a j-link, ruining the boatloader. Programming it with the j-link doesn't work either, which is beyond weird. I was able to debug it fine earlier, now the debugger can't halt the CPU anymore.

If anyone has good instructions on flashing the bootloader with j-link, I would appreciate.

So my score until now:
2 dead M4's due to unknown reasons
1 dead due to killed bootloader when experimenting

I have the slight suspicion that it is indeed the bootloader on all three of them, although I have no idea how I could have killed it on the first two boards.
I always had trouble flashing them with platformio, where I often had to try three times to flash it once.

The M4's are definitely a different experience to what I was used to from other Feather boards.

[turbinenreiter]

Ok, I was able to ressurect the board where I broke the bootloader.

• build the bootloader

  Code: Select all

  make BOARD=feather_m4

  from https://github.com/adafruit/uf2-samdx1/ ... -README.md
• hook up the Feather to the jlink according to this pinout: https://docs.platformio.org/en/latest/p ... onnections
• start

  Code: Select all

  JLinkExe

  (I had to use sudo altough I installed the udev rules ...)
• within JLinkExe:

  Code: Select all

  si 1 // switch to SWD
  speed 4000 // set speed
  device ATSAMD51J19 // set device
  loadbin build/feather_m4/bootloader-feather_m4-v2.0.0-adafruit.7.bin, 0x00000000 // this flashes the given file to the given address
  r // reset
  g // run program
  

Now I'll try to resurrect the others with this. Thanks to jerryn on discord for some valuable pointers.

[adafruit2]

we just checked and we didn't lock the bootloader on the feather m4 in test, so if you're not using UF2 or Arduino it is *possible* you could get it overwrite the bootloader somehow (not easy but...)
we'll check that going forward all M4's come with locked bootloaders!

if you have an M4 that is fine, you can lock the bootloader by 'upgrading' the UF2 bootloader, the upgrade.uf2 will lock after update: https://github.com/adafruit/uf2-samdx1/releases - just doubleclick to get into bootmode, and drag the correct 'update-boardname.uf2' over

[turbinenreiter]

Resurrection successful, beer for me, love and respect for the people!

[adafruit2]

:) thanks for finding this - we will fix our production jigs

[BryonMiller]

Resurrection successful!

Does this mean you were able to get the first two back? I must have a different problem because I don't have a drive to drag the uf2 file over to. Even after a double push.

[turbinenreiter]

I had to re-flash the bootloader using a j-link, and now it works again with the double-click and drive.

The list with the codeblocks a couple of posts up is a little how-to - but you need a segger j-link and some time. I think the instructions are complete, but there is a lot of implicit stuff ... so if you have a j-link and want to try, I'll be here and try to help.

[adafruit2]

byron if you dont have a jlink we can replace it - but when you get the new one please update the bootlader!

[MakerMelissa]

I'm having a similar issue except with an Itsy Bitsy M4 Express. I just ordered a J-Link programmer so I'll update this after I get it to let you know if it works. I'm pretty sure I know how I caused it too. I had 4 Neotrellis boards using the 3V pin. I think they pulled too much power (the regulator is rated to 500ma) and I think the chip became underpowered and that might have caused the bootloader write protection to fail. Hope this helps with possible causes.

[MakerMelissa]

Just got my JLink tonight and this fixed it. Things to note regarding above instructions:
[*]Since this was a different board, different chipset. This one has an ATSAMD51G19A
[*]Although not explicitly noted, you need to power the board with USB in addition to connecting the JLink

[bradl001]

Is this J-Link programmer the best way to, hopefully, get an M0 adalogger recovered? Is the process explicitly detailed?

Clearly, I don't want to spend more $$$ on something to fix a $20 part but, perhaps, there is a recovery service available (i.e. I mail it in, you fix and mail it back)...

[MakerMelissa]

I decided to buy a J-Link instead of another board for the following reasons:
1. I was fairly sure it would work
2. Now I have a J-Link in addition to a working board for just a little more money
3. If it ever happens again, I can do it without spending any more money
4. I was really interested in what would be involved in getting a blank circuit up and running
5. The found the knowledge gained in the process far more valuable than the cost of the programmer