Hmmm, I don't know about that RPC stuff. A friend of mine got this drive and gave it to me to upgrade. It came with 2.07 and I flashed it sequentially up to 2.11, in the end my hardware region counter did not change once.
Also, I was able to use LtnFlash to make a backup of the drive's 1MB firmware, but I didn't try flashing it back onto the drive since it's not my own drive. Has anyone had the guts to try LtnFlash for flashing? Don't try flashing one of the bin files from the official updates onto your drive since they're only partial firmwares. If someone wants the 2.11 that I extracted from the drive, to try to flash it onto theirs with LtnFlash, just let me know.
I suspect that Sanyo is using a similar flashtype to the upcoming Lite-ON DVD burners, but this does not mean that they're the same drives.