grub.cfg

menuentry "USB installer" {
    search --set usbdev --no-floppy --fs-uuid 555517bf-ff25-4d56-ab44-007555156b76
    loopback loop "(${usbdev})/usb.img"
    set root='(loop)'

    linux   /boot/vmlinuz ro quiet splash root=UUID=555517bf-ff25-4d56-ab44-007555156b76 puavo.img.dev=/dev/disk/by-uuid/555517bf-ff25-4d56-ab44-007555156b76 loop="usb.img"
    initrd  /boot/initrd.img

    loopback -d loop
}