BIOS update DEC750 fails

[mischa]

Hi everyone

I'm currently trying to update a DEC750 appliance to the latest BIOS version according to these instructions:

https://docs.opnsense.org/hardware/bios.html

I have tried various USB sticks and the Linux image as well as the Windows installer. As soon as I choose the USB drive to boot, the console screen just turns black with a blinking text cursor; consequently the update does not succeed.

I also tried to access the EFI shell directly, which unfortunately leads to the same result...

Any hints on where I'm going wrong here?

Many thanks

Mischa