mountroot()
{
  set -x
  mkdir /cdrom /btrfs
  mount -t iso9660 /dev/sr0 /cdrom
  mount -t btrfs -o loop,subvol=ROOT /cdrom/live/filesystem.btrfs /btrfs
  modprobe brd rd_size=$((256 * 1024 * 2))
  btrfs device add /dev/ram0 /btrfs
  mount -o rw,remount /btrfs
  mount -o move /btrfs /root
  mkdir /root/cdrom
  mount -o move /cdrom /root/cdrom
  set +x
}