A few weeks ago, when I was moving my reform the the V3 image and trying to boot from eMMC, my reform stopped booting. I think I damaged the SOM. The tool I was using to flip the switch to boot from eMMC slipped and knocked into the SOM. There is no visible damage and it was not a hard impact, but it has not been able to boot since.
Switching back to SD boot did not help, and I know the image on the SD card was previously working.
I have not been able to get a serial connection working.
The OLED screen and keyboard are working fine. Battery status displays correctly.
The Green light on the SOM turns on.
Any advice on troubleshooting?
Specific points on the SOM I should check with a multimeter?
I don’t have much experience trying to fix SMD boards, would it be worth it to try using a heatgun to reflow some solder?
I’ve thought about finding another SOM somewhere to purchase, but nowhere seems to have the Nit8MQ_SOM_4r16e in stock in the US.
Any advice on how to fix this is appreciated.
I wish I had an answer for you. I was surprised that neither Mouser nor Digikey had the Nitrogen SOM in stock.
I’ve actually been holding off on moving to the eMMC because I’m a little worried about bricking my system.
See if a brand new image flashed to the SD card will boot (making sure the SOM switch actually did get set all the way back to ON). You can also (haven’t tried this myself) boot from USB: document boot options (#2) · Issues · Reform / reform-handbook · GitLab
I believe there are a few test points (exposed pads large enough to probe with a multimeter without bridging neighboring pins on any of the tiny connectors) on the SOM you could check, but I don’t think the SOM is in the Reform schematics. You would need to see if they’re described in a datasheet for the SOM.
No, unless you can identify a broken solder joint (press gently with a nonconductive tool against IC legs or whatever component you hit to see if there’s movement in the component independent of the board) it’s usually a bad idea to just heat up everything. On top of that, these boards almost definitely use lead-free solder (I think RoHS prohibits it), and lead-free solder is notoriously hard to melt, especially with indirect heat, so you probably wouldn’t reflow anything anyway. If you do identify a broken solder joint, it’s probably better to use a soldering iron since the break should be at just one point.
So, even though Mouser doesn’t keep the iMX8M SOM in stock - you can order it through them. I requested a deliver quote because I was curious, and they are saying that they have a 4-6 week factory lead time.
Out of curiosity, would other Nitrogen SOMs work with the Reform?
Currently only Nit8MQ_SOM variants are supported, but I am working on an adapter for the 8MPlus SOM as well (it does have one less PCIe lane, though—but there is an option to have WiFi/BT on the module itself).