efibootmgr triggers UEFI firmware problem

[Patrick Oltmann]

Dear all

I recently used efibootmgr (0.5.4-12.fc17.x86_64) to inactivate a couple
of UEFI boot menu entries and change the default boot order on my 
Thinkpad X220 (UEFI version 1.33). When I re-booted the machine
afterwards, the UEFI menu showed up with the desired entries and order, 
however selecting the entries (both Linux and Win-7) only blanked the
screen briefly and then returned to the menu. After a long troubleshooting 
session I found that the issue originated from the firmware's failure to 
properly unlock the self-encrypting SSD (Intel 520 series), which makes
the drive (which holds the EFI partition) non-existent for the UEFI boot 
loader. All the entries in the UEFI menu, especially the paths to and within 
the EFI partition, were as far as I judge correct, so efibootmgr didn't do 
anything that would have been obviously wrong.
Nevertheless, the question how efibootmgr triggered the firmware problem
still bugs me (the machine was running with the same hardware/firmware 
configuration for 10 days before). I'm still in the process of getting familiar 
with the concepts and implementations of UEFI, so I was wondering whether
there would any explanation for it.

Thanks & best regards

Patrick