Do you mean DOS or an NT command prompt? AFAIK, most BIOS updates are done in either DOS or GUI Windows. A command prompt only NT is a bit tricky, and not very useful anyway. A DOS booting USB stick ...

Hi.. I'm currently back on macOS but ran Ubuntu 20.04 on my iMac for ~4 months exclusively. As in no macOS install at all. Purely Ubuntu. At least once a month, my boot disk would revert to read only.