Krow
Garbage Connoisseur
If it's a windows update, USB boot and roll back the driver.
If it's a BIOS update, get the previous version from Lenovo, follow the instructions downgrade the bios. Most Lenovos have a setting to stop downgrading but it can be changed for emergency situations.
To follow up on this a bit more, I believe my BIOS is corrupted in some way because nothing I do at all will let me access the BIOS menu. None of my function keys will do anything at all, the NOVO button boots the laptop to the same Legion splash then sticks there. Doesn’t actually open the BIOS menu at all.
The only keyboard input that works (that I’m aware of) is ctrl+alt+del which just restarts the endless boot loop again.