SBSFU | Option bytes programming and OpenOCD

[Jakub Standarski]

Hello all,
Another question from SBSFU series.
I'm wondering what are the available ways to clear option bytes?
The option I was using so far was simply STM32CubeProgrammer GUI, but what if we don't have ST-Link on board and we have to rely on something else like FTDI?

I've tried to connect to the programmed board (i.e. with SBSFU installed and securities turned on) via OpenOCD, but I'm unable to connect, here is the output:

Do you think that's because of securities turned on?

Thanks in advance!

[Jocelyn RICARD]

Hello @Jakub Standarski ,

yes, by default SBSFU enables protections, so it is not possible to debug.

You should first perform a regression, setting RDP level from 1 to 0 and clean possible option bytes using the STM32CubeProgrammer.

Then disable the protections in SBSFU before downloading again.

Best regards

Jocelyn