Can't downgrade from 0071 bios, the usual recovery methods including pulling the security jumper and the power button menu do not work. 0071 bios includes security updates and is one-way upgrade.

With this bios you can't boot, to fix this you need to add a patch for RTC to the clover DSDT patches.:

<dict>
  <key>Comment</key>
  <string>Fix NUC BIOS DSDT Device(RTC)</string>
  <key>Di

Using the instructions to update to Big Sur, I've now landed on this grey screen. Using the latest EFI release. USB installer went fine, then booted to macOS disk, rebooted once or twice, now I land at this grey screen whenever I boot from my macOS disk. Any suggestions? 2018 MXPro i7/MX150. The only changes I made to the config.plist was to change smbios values. Thanks in advance for any help.