How to unbrick Somu
Recently, I accidentally put the wrong firmware on a Somu, thereby bricking it.
In order to unbrick it, it is necessary to link it with a STLink.
See the following schema to have the correct pinout (taken from here).
Don’t forget it may be mirrored from what you are seeing. Use the the clues and asymmetries in order to figure out which pin is which.
The following correspondance must be made:
| Schema | STLink |
|---|---|
| PE | GND |
| +3V3 | 3.3V |
| SWDIO | SWDIO |
| SWCLK | SWCLK |
It works with STLink clones, see the following for correct pinout (taken from here).
You can get more info on this website.
If you don’t want to solder, with a steady hand it’s possible to put 4 wires on each pad. With the help of automation or another person, it is possible to flash without soldering.
Then issue the following commands:
st-flash reset
st-flash erase
st-flash --reset --format ihex write bundle-hacker-4.1.5.hex
After this step, unplug & plug again the Somu(Hacker) and you can use regular dfu tools. You can also use the solo tool.
Look at this ticket on GitHub for more information.