Rather than treat both as the same, since untethered has everything up front anyway, go ahead and extract the filesystem.
This makes the mount look more straightforward and makes it so deletion of files from
the image also frees ram.
If debugssh is not requsted, the initramfs is not needed.
Do not unshare the mount namespace, leave the kernel relevant namespace 'normal'
Remove some initramfs content to free up some memory.
