What were you trying to do that didn't work?

A customer updated linux-firmware to latest linux-firmware-20251008-151.5.el9_6.noarch.
After reboot the system hangs when microcode is being applied, whatever the version of the kernel.
Booting with "dis_ucode_ldr" works.

Below is the relevant CPU information:

processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 26
model           : 2
model name      : AMD EPYC 9555 64-Core Processor
stepping        : 1
microcode       : 0xb00211a

The above microcode field is the current microcode, i.e. not the one shipped by latest linux-firmware but the "standard" one.

What is the impact of this issue to you?

Can't boot

Please provide the package NVR for which the bug is seen:

linux-firmware-20251008-151.5.el9_6.noarch

How reproducible is this bug?

Always on customer system