Wierd Drive Versions and FAQ Overclocking Question

I read here http://www.goldenhawk.com/devices_body.htm and here http://www.vob.de/Devices/RecorderL.htm some LiteOn drives that I had not heard of before. While this could just be catch all drive names for these programs, they could also be genuine. I searched the forum here and read that a LTR-40126S was supposed to be released a while back. I guess they just skipped it and went ahead with the LTR-48126S. It would be nice to find this drive if it was released though as it would be cheap and could probably flash o/c to 56246S.

Lite-On “LTR-40126S” SANYO CDRW401248

Here are some more. I have not seen the H, K, or G eeproms before, or those 7 series drives (cut and paste):

LITE-ON LTR-32123H
LITE-ON LTR-32125K
LITE-ON LTR-3248MH
LITE-ON LTR-40125K
LITE-ON LTR-40126H
LITE-ON LTR-40126K
LITE-ON LTR-48125G
LITE-ON LTR-48166K
LITE-ON LTR-48246K
LITE-ON LTR-52246K
LITE-ON LTR-52327K

Another Question about the FAQ, it states (cut and paste):

LTR-12102B: Not upgradable, mediatek chipset [Personally tested]

LTR-12102C: Not upgradable? mediatek chipset. [Not tested by me]

LTR-16102B: Not upgradable, mediatek chipset [Not tested by me]

LTR-16102C–>LTR-24102B, possible, mediatek chipset. [Not tested by me]

LTR-24102B: Not upgradable, mediatek chipset. [Personally tested]

I own an LTR-24102B, so not that it truly matters to me, but why aren’t the firmware interoperable between all series 2 drives?

Edit: I searched the forum and found out that someone thought the K’s might be DVD combo drives or dvd recorders, but wasn’t sure.

Edit 2: I read some more, and answered my second question. It is the 8Mb cache on the faster drive compared to the 2Mb cache on the slower drive that keeps one from upgrading within this series. One CAN however downgrade, I believe. Still wondering about the first question though.

Edit 3: Ok, I searched around, and found that all three drives (LTR-12102B, LTR-16102B, LTR-24102B) have 2Mb cache. What gives here?