1) Download the PUP (PS3_Custom_Firmware_v3.55_Backup_Manager_Patched_ Wutangrza-kmeaw.rar)
2) Un-rar it to your PC, put it in \PS3\UPDATE\ folder on USB stick
3) TURN OFF YOUR PS3 (if turned on)
4) START YOUR PS3 in NORMAL RETAIL MODE (do not use JB dongles)
5) Plug the USB with the PUP and update from "storage device".
That's what I did.
I believe a lot of users got in trouble by updating from JB mode... I don't know. All I know is that I waited and read a lot and all is okay from my first try.
I even backed up LittleBigPlanet with the eboot_fix method so now I have it on both my PS3s (even without the need for JB or syscalls).
Dean, sorry the off-topic, only for this question I have some PSN games installed and now that I decided to format my PS3 do you think that if I do a backup of them will they work after I FTP them back?