How to program a Discovery board after Brown-out level set as mass write fails

[Robmar]

Using STM32IDECube, I set the Brown Out level to 2 for our board, which works fine on it's own power supply, but now trying to update the firmware over USB, ST-Link can´t write to it, it does't boot, and I can't see how to override the BOR level from the Cube Programmer.

[Robmar · Accepted solution]

Okay fixed, so in Cube programmer I had to set it to connect "Under reset", then in OB, Option Bytes, set the BOR level to 3, Apply, repeat the above once more as the first time it didn't seem to work, then bingo, the chip can be read and written again!

I assume that the USB debug connection does not give a suitable voltage for BOR level 2, so the chip was halted.