CONFIG_MICROCODE_AMD was removed in Linux 6.6.0 https://www.phoronix.com/news/Linux-6.6-x86-microcode https://lore.kernel.org/lkml/20230828122533.GBZOySPQIjw25NiUqI@fat_crate.local/ genkernel still requires it though. Reproducible: Always
See https://bugs.gentoo.org/913659 for a quick and dirty patch for genkernel 4.3.8.
*** This bug has been marked as a duplicate of bug 913659 ***