[CentOS] After update to 8 (2004) ... system is unbootable - UEFI Secure boot

Wed Jul 29 18:54:47 UTC 2020
Phil Perry <pperry at elrepo.org>

On 29/07/2020 19:43, Leon Fauster via CentOS wrote:
> Did you got managed to boot kernel-4.18.0-193.14.2.el8_2 or a newer one?
> I must still boot into kernel-4.18.0-147.8.1.el8_1.x86_64 ... and with 
> the upcoming new kernel that depends on a new shim and grub2 package I 
> wonder about the implications for my XPS hardware ...

The following article discusses a way to add a hash for older kernels to 
the Allow List that should allow older kernels to continue to boot:



Red Hat Enterprise Linux 8

Due to hardening within the kernel, which is released as part of these 
updates, previous Red Hat Enterprise Linux 8 kernel versions have not 
been added to shim’s allow list. If you are running with Secure Boot 
enabled, and the user needs to boot to an older kernel version, its hash 
must be manually enrolled into the trust list. This is achieved by 
executing the following commands:

# pesign -P -h -i /boot/vmlinuz-<version>

# mokutil --import-hash <hash value returned from pesign>

# reboot