Comment # 14 on bug 1201066 from Joey Lee

(In reply to Kilian Hanich from comment #12)
> OK, U-Boot follows the "Embedded Base Boot Requirements Specification -
> Release v1.0" and as such does not have a full blown UEFI implementation.
> This includes that "SetVariable" is not supported.
> 
> efivarfs gets mounted because systemd does that. And as such mokutil thinks
> it is working with a full blown UEFI implementation.
> 
> Now, I tried to just add "noefi" as a kernel parameter and I have not
> noticed any bugs. Because efivarfs doesn't get mounted, mokutil acts
> properly and as such transactional-update actually succeeds updating.
> 
> So, does somebody know if anything else depends on being on an UEFI system?

There have following functions need efivarfs. All of them need SetVariable:

- rtc-efi
- efibootmgr
- MOK
- uefi capsule update

For reading requirement, "mokutil --sb-state" needs efivarfs for detecting
"secure boot" status. But I am not sure who used it.