Line 570 in /usr/share/genkernel/defaults/initrd.scripts says: if [ "${USE_MDADM}" -eq '1' ] this should be if [ "${USE_MDADM}" = '1' ] as "${USE_MDADM}" might be an empty string, and then -eq will fail. There are other simliar checks in the same script, and they all use = instead of -eq. Reproducible: Always
Excellent catch, thanks for reporting. This has been fixed on the experimental branch exposed by genkernel-99999 (five nines). http://git.overlays.gentoo.org/gitweb/?p=proj/genkernel.git;a=commitdiff;h=532dd7a3871e389351d115fb19db73532bb6dd5b