Please Fabby :
menuentry "gparted" {
set isofile="/gparted-live-0.31.0-1-amd64.iso"
loopback loop (hd1,4)$isofile
linuxefi (loop)/live/vmlinuz boot=live components config findiso=$isofile ip=frommedia toram=filesystem.squashfs union=overlay username=user
initrdefi (loop)/live/initrd.img
}