Can't enable fastboot the second time?

Hello everyone,

I have been playing around with the DragonBoard 410C this morning. I followed the tutorial on this PDF ( and failed at this command:
fastboot flash sbl1 sbl1.mbn
However, I continued to do the rest of the tutorial. After finishing, it could not boot (completely black screen, I guess I messed up somewhere) but now, I cannot turn on fastboot anymore (fastboot devices shows nothing). Can anyone show me what is the problem here? I would be very appreciated.

how did the command you mention fail?

sbl1 is the primary bootloader, if it is not flashed correctly then the SoC won’t be able to boot, the board is said to be ‘bricked’. IN the user guide you should have a chapter that explains how to use the ‘rescue’ image for such situation.

Hmmm. Apparently I did not read the guide thoroughly, there is actually a section for my case. I will try following it, thank you for your response.

It worked. Thank you so much.