As I understand it, some 2002 ME7.5 ECUs are unique to that year only and can't support bins from newer (2003-2005) ECUs. I know that the 8E0909518F is one of those '02-only ECUs, but are there any others? I have an 8E0909518G from an '03 CVT, and I'd like to know if I can flash an 8E0909518BC (or other later manual transmission file) to use as a backup for my wife's '05 A4.

Does anyone have a definitive list of what's compatible and what's not in the '02-'05 range?

you can flash the same SW with different version ,EG. 8E0 909 518 AF 002 to 8E0 909 518 AF 003  safely .
crossflashing different SW numbers is always a gamble ,it may work it may not work properly or in worst case it may brick your ECU.

Have a bench cable prepared just in case and just try it.

Here is what I use:

2002 8E0909518F
2003 8E0909518AF
2004 8E0909518AK
2005 8E0909518BC

You can use AK on BC and vice versa, but BC doesn't work properly with the nefmoto software.

I can tell you what the 518G ecu is compatible with if you post the file that came off of it.

Compatible with 518F.

MY 02 ecu.

I don't think I have a 518F spare, LMK what you want for it if its of no use to you.

I could trade you a B5.5 passat ecu that will take the 518AK file.

Email me.

ddillenger84@gmail.com