As a result, mdadm arrays are still assembled by my livecd filesystem, but they're not assembled by the initrd phase.
It seems to me that this *should* be OK when building a livecd, but I'm not knowledgeable enough to know if it has some other undesirable consequeunces. If I run into anything, I'll make sure to reply here...
Possible workaround:
I discovered that my livecd boots all the way through if I remove the mdadm hook from iniramfs:
rm /path/to/ livecd- chroot/ usr/share/ initramfs- tools/hooks/ mdadm
As a result, mdadm arrays are still assembled by my livecd filesystem, but they're not assembled by the initrd phase.
It seems to me that this *should* be OK when building a livecd, but I'm not knowledgeable enough to know if it has some other undesirable consequeunces. If I run into anything, I'll make sure to reply here...