Please apply this patch https://git.kernel.org/cgit/linux/kernel/git/kees/kmod.git/commit/?id=572a2711e711edb1810c88b124b709fa58f80880 that fixes the -P argument for prefixed targets I tested this patch against kmod-12-r1 and works fine!
I just spoke with upstream and was advised that the kmod-13 release is imminent (probably in the next 48 hours).