Comment # 3 on bug 1209024 from Michal Suchanek

Works with later kernel:

Linux jostaberry-5 6.3.0-rc1-1-kvmsmall+ #1 SMP Tue Mar  7 18:47:04 CET 2023
ppc64le ppc64le ppc64le GNU/Linux

 file /etc/uefi/certs/1F673297.crt 
/etc/uefi/certs/1F673297.crt: Certificate, Version=3,
Serial=00fabed8bf409a5e65, Issuer=openSUSE Secure Boot CA