Any firmware from this site.
Personally I would recommend : LD_2TC.zip Liggy & Dee 2.TC RC3, based on MD16 2.FC with riplock removed and RPC1 (NEW 08-04-2005)
since i use myself version 2.TB which suits all my needs - booktype, region free drive and riplock removed
However if you want to do the best for your drive I recommend supporting it with a DVD-ROM by Lite-On (for great error correction capability) or any other of your choice - this way you extend life period of your drive. Should you decide to do so - you may as well consider obtaining a combo drive - DVD-ROM and CDRW in one device.
Keep in mind that stock firmware has a riplock - but not for teasing end users - it is so - to prevent errors durring extraction. Another important fact is that switching to non-original firmware may result in voiding your warranty (there is a chance it won't be invalidated if you flash it back before RMA).
For the flashing purpose use this tool
I switche to modded firmware to have booktype for "plus" format. This was the only reason.