Hi, Pascal > IIRC and although it did not change with Buster, the initrd.gz in > installation images does not include the loop module either. So it is > not able be able to mount an ISO image. Yes, you are right, neither could i mount ext4 partitions within busybox But it is able to mount vfat partition, maybe it's for UEFI? Tested with debian-9.9.0-amd64-netinst.iso Thank you for the information -- Liu An