Efi Shell Version 260 512 2021 -

If you are in the shell to update your BIOS:

Cause: Faulty add-in card (GPU, RAID controller).
Solution: Remove suspected hardware, or use pci -i to disable problematic devices. efi shell version 260 512 2021

setvar PK -guid ... -bs -rt -nv = 0x...
  • Reboot into shell on that media; startup.nsh executes.
  • Use Mok/KeyTool .efi utilities if available to manage keys.