Firmware choice for nec 2510a

Good time of the day!
What are the best of firmwares for SL and DL media (bitsetting, media support) at this time?
Do we have one firmware for both SL and DL to set booktype (bitsetting) for +R/RW as DVD-ROM?
What are differences between TDB’s and Herries’s firmwares for the same official firmware ( for i.e. 2.16)?

TDB’s only make the firmwares region free, remove the riplock, etc. They don’t make and write strategy changes, Herrie does. The only firmwares that can change the booktype for both single and double layer media are the HP 520N firmware or Herries modified firmware based on this HP 520N firmware. Please check out the NEC forum int he Recording Hardware Section for more information.

Thanks a lot dhc014! I will look at that section. It seems to me that branch more popular for NEC holders :).