Tried with 3.1 on PPC Mac.
Strange results. Sometimes internal partition mounts, sometimes memory stick partition mounts.
Internal partition still doesn't work. - I guess the Mac team haven't had access to a firmware updated PRS-500 yet..
Correction - sometimes it takes a long time for both partitions to mount
Internal partition still produces error, memory stick works.
Tried with 3.1 on PC.
Both partitions take longer to mount now! Not sure why..
The only concrete difference I can see offhand is the change in name to "Reader Library" and the PRS-500 shows up as "Reader".