[CentOS] Centos 7 shim fix failed

Wed Aug 5 00:01:38 UTC 2020
Leon Fauster <leonfauster at googlemail.com>

Am 05.08.20 um 01:27 schrieb david:
> At 04:18 PM 8/4/2020, you wrote:
>> Am 05.08.20 um 01:09 schrieb david:
>>> At 01:54 PM 8/4/2020, you wrote:
>>>> On Tue, 04 Aug 2020 13:44:05 -0700
>>>> david wrote:
>>>> > After all the updates, the system was NOT bootable.
>>>> How long did you wait for it to boot, and what did it do when it 
>>>> failed to boot?  What text messages showed up on the console?  Any 
>>>> reported errors when you ran the update or when you rebooted the 
>>>> computer?  If so, what did the say?
>>>> I personally haven't had any issues updating any of my computers 
>>>> (using a mix of Centos 6, 7 and 8) but maybe they're all too old to 
>>>> for the issue to show up.
>>>> -- 
>>> How long did I wait:  5 minutes
>>> What on the console:  nothing, just a dull gray color
>>> Errors on update:  none
>>> ---------------------
>>> But when I blocked the update, it booted within a minute, and ran.
>> Can you boot the system with all updates and secureboot=off?
>> (Just to be sure; I imply that you use UEFI, right?)
>> -- 
>> Leon
>> ____________
> I'm not sure how to turn 'secure boot' off or if it exists.  
> (MacMini5.2).  I presume it uses UEFI, but not sure how to answer that.

Oh, an apple device. AFAIK the openfirmware of such hardware have also a 
legacy mode. So first check if it uses the UEFI mode at all by checking
if this directory exists (in the working/bootable system):

# ls -la /sys/firmware/efi

if so test the secure boot state with

# mokutil --sb-state

> Boot failure only occurs when the grub2/shim/mokutil updates are applied.