I have a 2000 audi a4 1.8 turbo and have picked up the cluster from a 2000 1.8 turbo Quattro (they are white) I have managed to get the skc from both and have installed the new cluster and tried to match it to ecu, but I am still getting engine start blocked by ecu ( keys are matched to the cluster but I don't think the cluster is talking to the ecu)   old cluster was vdo revision d11 and new is revision d12, I have tried the eeprom from  the old cluster on the new dash and get the same result, any ideas?

immo light went out and no longer flashes, but cluster has old cars vin number still, from what I understand I need adaption channel 50 but it does not connect

You did not match the ECU to the cluster successfully. That is your problem.
Im sure you know how to but here is the procedure

-Instruments 17
-Login
-With "NEW" clusters PIN
-Adaptation
-CH-50
-READ
-New value
-Enter "Your" cars PIN
-Test
-SAVE
-Match keys with your cars PIN

Done...

You dont if you know the PIN of the used cluster.

-USED = you need to log in with the PIN to adapt
-VIRGIN = You do not log in to adapt.

Either way you still need your cars current PIN though.