add missing boot entries or overwrite allreturn the ESP partition as a Filesystem (for adding to fstab)in recovery, boot entries should be correct.

run mdadm to create and start array.

ExistingFs creates a Filesystem struct corresponding to a fs that already exists.

find recovery volume by looking for the fs label.

find the raw disk(s) we'll partition and install to.

modified version of io.Copy().

determine whether system is uefi or legacy and make it bootable.

partition recovery device.

Assume recovery volume will have label imaging.RecVolName(), and read a file 'platform' from the root dir.

Format boot partitions, write files to them.