Driven by the recent accidental crossflashes of 20A3S to 20A3P, that still left the drive detectable by Windows, I decided to try the DRU-840A to Samsung SH-S203B crossflash.
Unfortunately the drive only worked until the next system reset. On the SiI0680 card it disappeared from Windows and when connected to one of the standard IDE ports the system hung looking for a raid drive.
S203B: FAILED AFTER RESET! DON'T TRY THIS AT HOME!
And in case you're worried, the drive is back happily running as a DRU-840A again.
The flash to SH-S223F just left the drive in DRU-840A boot mode and was able to be flashed back to SS01.
S223F: FAILED TO LEAVE BOOT MODE
Anyway attached is the first and only burn using stock S203B SB04 in the DRU-840A.
DRU-840A SS01 burn of the same media here:
Ignore the PIF difference, as these Prodisc MCC004s produce these random PIF clusters, which vary from disc to disc.