Hi! I hope i can get some help too. I have similar problem.
I swapped my B3 coupe quattro to 1.8t AEB , and I'm using an A6 c5 1.8t cluster.
I have to mod the speedo and fuel gauge. I find a write up with the gauge scale bit locations so i tried to calibrate speedo first.
It worked out good now my speedo shows exact speeds, but now i have 'def' on the trip display...
I tried to find out how i can corrigate the checksum but find no info about it. Any help would be great.
I post the original and modded dump too, maybe somebody can help to find checksum.
cluster is: 4b0 920 980 H

Yes i already fitted eu scale (km/h 260)  from a similar tdi cluster, and recoded the IC for Eu coding (00144). From other topics and posts I guessing the speedo map checksum bit is 0xb2, but I have no idea how to correct it or is this the only cheksum bit...

Mod is not just about to fit the eu scale, but correction for the different signal from the gearbox due to the AEB swapped to the original 01A quattro gearbox... Maybe I have to calculate and change K value too?

It's perfect!! Thank you very much!
As I eyeballed to the gear and rpm the speedo shows proper speeds, tonight i will check with gps.
May you tell me how you did it? I see you changed both axis of speedo map , but the other bits? all for the checksum?