skikky94 wrote 66-disable -t boot tty12 All
All can't be disabled because is a part of boot@ system

Maybe it should be emphasized more in the quick reference section. tty12 and All are disabled before the new module is enabled. You seem to have enabled the module and then tried to disable boot and All.
From chroot, since you can't boot,

66-tree -R boot
66-tree -n boot
66-enable -t boot -F boot@ system

and it should be ok.

BUT

mount-fstab may be a different issue. Are you sure nothing has changed and no invalid entries exist in fstab. From chroot if you # mount -a do you get any errors?
It may be because on your boot tree you have both boot and boot@ system enabled so the same service mount-fstab can't run twice (I think, I'm not sure what is going on) but fix your boot tree first and try it again.