I have Lenovo ThinkPad E530 with BIOS 2.58 (latest). Once I changed boot mode from UEFI to Legacy, I cannot enter BIOS settings or choose boot device. I cannot boot to my OS (Windows 10) either.
How do I change boot mode back to UEFI?
Found it! Just needed to unplug CMOS battery, shorten its pins for 10 seconds, then plug it in. After that, there will be a message saying that CMOS Time settings are wrong and after that you can enter BIOS. It's awful, Lenovo, I've spent 3 hours digging that info up.