Comment # 141 on bug 1173158 from Martin Wilck

(In reply to Jiri Slaby from comment #140)
> Note hat efivar_entry_set_get_size returns EINVAL in some cases too.

Thanks, I misread the error code mangling in efivarfs_file_write()...

>  * Returns 0 on success, -EINVAL if the variable data is invalid,
>  * -ENOSPC if the firmware does not have enough available space, or a
>  * converted EFI status code if either of set_variable() or
>  * get_variable() fail.

And here we have "EFI_INVALID_PARAMETER" mapped to -EINVAL. Which could thus
basically mean anything :-/.

>From the fact that the same operation failed under kubuntu as well (comment
135), we might infer that the EFI layer rejects the users's certificate for
some reason.