@d00d Thanks for following up with the clarification of where the problem originated. Did you find a place to rebuild your cluster?

No, unfortunately, had to buy a new one!

But if anyone is interested, I did find possible (forums) evidence that all of the relevant info like the VIN and such is stored in the EEPROM. I did try swapping that chip (only) over to the eBay unit but was unsuccessful. Possibly because the original chip had been damaged already or possibly because I damaged it in the process or possibly because that was bad info for the SC and it won't work anyway.

I also tried using a BMW programmer (actually a $30 Chinese clone off eBay) which also turns up in forums as a possible way to reprogram a cluster but it only saw a few random things (e.g. HVAC) and was of no use.

(I do have pics of the cluster teardown for the chip swap but as it was ultimately unsuccessful didn't bother to post them.) 2008 SC L322
2001 P38, Epsom Green, fully restored SOLD

Interesting - no faults but I randomly did an iid to scan by accident as my eas compressor is dying and it came up with an immobiliser can fault and a u2600 module software fault? Could this be the beginning or am I worrying over nothing? Ironically I have a spare cluster in the shed which a bought for troubleshooting years ago - if I could swap the eeprom and know it would work that would be a good shout I guess Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF