LiteON DH20AH4 - QP5B PC drive DVDRW All Write Lightscribe

On Fri, 13 Nov 2009 12:58:17 -0500, Meat Plow put finger to keyboard and composed:

I would have thought that corrupted firmware (bad checksum) would not allow the drive to pass its self test.

Can you compare the backup with the downloaded version?

In a Windows DOS box you would type ...

fc /b backup_fw.bin QP5B.bin

- Franc Zabkar

The firmware can be hacked to provide functions it would not normally support so the fault may lie in that area and not necessarily cause a self test failure.

The firmware is loaded by its own imbedded loader in (QP5B.exe) so I have no new bin to compare. Best I can do is backup the current firmware and compare it to the one in question.

On Sat, 14 Nov 2009 11:01:28 -0500, Meat Plow put finger to keyboard and composed:

I have hacked the firmware in my old Ricoh 2x CD burner, and in an old Award 386 motherboard. Both devices required that the checksum be recomputed. On my first attempt with the Award BIOS hack, the POST complained of a BIOS (not CMOS) checksum failure. Therefore it appears that one of the first tests that a uP does after it powers up is to verify the integrity of its firmware. This was always the case with the minicomputers and periperals that I used to service. I suspect that it still applies to most, if not all, uP based gear.

- Franc Zabkar

I understand that a unique checksum is generated each time bits in the firmware code are changed and they must match but in this case that was overlooked in some unexplainable manner. All I did was reload the same bin I did several months ago and the device now functioned in every mode it advertises not just DVD and Lightscribe like I had been using it for.

I have another device, a Pioneer DVD-RW 108 (circa 2005) 16X16 that I use for CDDA and out of curiosity put a CD in the LiteOn finding out it could not even initialize the read and just ejected the disc. I've used the LiteOn for CDDA prior to and after adding the Pioneer with the same bin aboard. I'll just chalk this up to one of life's little unsolved mysteries.