Giorgio

It's an upgrade, so as long as there isn't a way to get the V5.1-5004 up and running it won't be possible to install the U2...

Correct, but as DSM 5.0-4528 U2 also uses superblock 1.2 it can't be the cause of problem which we are having with DSM 5.1. I installed 5.1 on a simple bare metal test system and I see the following: Starting /usr/syno/bin/syncfgen... [OK] /usr/syno/bin/synocfgen returns 0 Partition Version=0 Partition layout is not DiskStation style. NOT EXECUTE /sbin/e2fsck. Mounting /dev/md0 /tmpRoot :: Checking upgrade file [OK] linuxrc.syno executed successfully. Post init init: Unable to mount /dev filesystem: No such device =================== start udevd ================ ===trigger device plug event ===== DiskStation login: