initramfs and bcache

I'm doing some testing with bcache on my Debian system, with the block devices layered like: sd[ab] md0 /boot (because grub doesn't understand bcache superblocks) md1 bcache lvm / And it almost works except that my bcache initramfs script runs after lvm. I told bcache to prereq on mdadm, so that much works, but unless I change the system provided lvm initramfs script, I can't get bcache to run before it, so I need to intervene at boot time to get it moving. Any suggestions? Thanks James