In the last few days, ala42 and us have successfully tested crossflashing BenQ DW1670 OEM (I/O Magic) to DW1670 retail/Sony DRU-820A and vice versa. The latest MCSE v220.127.116.11 now supports crossflash option for these drives. Many thanks to ala42.
The DW1670 firmware 004 that was used is a "development firmware" for internal testing purpose only.
Here are some screenshots.
I/O Magic (DW1670 OEM) crossflashed to DW1670 fw 004
I/O Magic (DW1670 OEM) crossflashed to Sony DRU-820A 1.0b
Sony DRU-820A 1.0b crossflashed to DW1670
DW1670 crossflashed to DRU-820A.