HP dvd840i woes

I got this drive recently, it came with FF66 firmware and has “Regulatory Model: GSA-4166B” on the sticker. It made 3 coasters with ImgBurn on Ritek and CMC discs right away and couldn’t work with my Verbatim 4X and 6X DVD-RW’s. So I decided to try it with LG firmwares 1.00, 1.01 and 1.02, which didn’t really improve matters. I started noticing that only 4X write speed was available in Nero & CDSpeed, regardless of the disc type inserted. After one of the flashes to 1.02 firmware however, I was able to burn a TY T03 at full 16X speed and with acceptable result (see attached). But when inserting a blank MCC 004 immediately thereafter, it showed only 4X again. The drive is jumpered as Master on Secondary IDE and I tried with both MS and nVidia drivers. Even in a USB enclosure, the same problems persist. Going back to updated HP firmware HJ86 doesn’t help either.

This is in another PC. I got one (almost) 16X simulation below, but 99% of the time it shows only 4X available with 16X TY and MCC media. I knew I was taking a risk when buying it, because the box had been resealed, but guess I was hoping if there was a small problem I could fix it. If anyone has any ideas, they’re welcome, but it looks like this one’s not a keeper.

How can I get this FIrmware?

P.S. I need firmware of Hp DVD840b. FF66

Do you need that particular firmware, or can you use this at firmware HQ?