Seems filesystem (/lib/modules/5.xxx-default) is different in emergency mode than what is on the actual filesystem on disk, so above comment might not mean anything. On the actual snapshot the module is present on filesystem (when booting into work snapshot and looking at the new (non-working snapshot) # ls /.snapshots/102/snapshot/lib/modules/5.14.2-1-default/kernel/drivers/block/ | grep xen xen-blkback xen-blkfront.ko.xz