You probably missed my second input - but it’s my bad so I’ll make an additional effort.
To be clearer (I’ll try), it’s possible that the base firmware used in the modified one that you have produces lesser burns with your unit than another base firmware would.
As an example: for the 3540, until 1.W5 Dee’s f/ws were based on NEC 1.01, 1.W6 was based on NEC 1.03, and 1.W7 and above are based on a MadDog f/w (don’t remember which one).
So if your drive “prefers” on of these base firmwares, or “dislikes” one, it’s possible that you get better burns with one of these f/ws than with a modified firmware based on a different stock firmware.
Uh. I hope this is more or less clear, I myslef have problems to understand exactly the point I’m trying to make LOL