[CentOS] 8.2.2004 Latest yum update renders machine unbootable

Sat Aug 1 15:02:17 UTC 2020
Lamar Owen <lowen at pari.edu>

On 8/1/20 5:00 AM, Johnny Hughes wrote:
> I would wait and install everything as a group. We should have 
> something soon. 
First off, Johnny and all of the rest of the CentOS team, thank you for 
your efforts!

Second, to all with this problem, I too experienced the issue (I posted 
on the CentOS-Devel list my findings).  To those who seem to think more 
testing could have prevented the issue, let me just say that while the 
FIRST update to the new shim-x64, grub2, and kernel stack failed for me 
(and that update was done with the GUI updater that reboots for the 
actual update), I WAS able to recover using the install media's rescue 
mode tools as documented in my posts on CentOS-devel.  I'm glad to 
provide any and all logs of the processes I did, but the short of it is 
that after I successfully downgraded grub2 it still wouldn't boot, but I 
was able to do a reinstall of grub2 (81, the older version) to get it to 
boot with the old grub2, the new shim-x64, and the new kernel, and then 
I was able to successfully update grub2 with dnf on a command line.  So 
I have the following installed:
[lowen at localhost ~]$ rpm -q shim-x64
[lowen at localhost ~]$ rpm -qa | grep ^grub2
[lowen at localhost ~]$ rpm -qa | grep ^kernel|grep 147
[lowen at localhost ~]$

And this is on a machine that previously crashed during boot with the 
exactly the same packages.  So even on the same hardware the same update 
(done a bit differently) had different results.

It's quite possible, based on my experience with this particular issue, 
that if I had the whole system rolled back to where it was before the 
GUI update and if I then updated it again that it could just simply work 
ok afterwards.  It's very hard to test for intermittent issues!