I knew this car was going to be a bear as nearly every time I've tried reading the ecu it always either

A: Reports security access was not granted/rejected
B: Reports security access is not supported

I have been able to start reading a few times (on those occasions security access was granted!) but all reads were painfully slow, and always failed between 7 and 30 percent)

Now I know the cable works as it flashes my 2000 a6 without issue. I finally was able to get a full read from the ecu after 7 attempts (I adjusted port speed and latency, not necessary on my other car), and decided what the hell, might as well give flashing a go. Anyway, I had to reconnect several times (cycling the key, then hitting reconnect, then re-writing the failed sector) before I was finally successful., Attached is the log. Any idea what gives? Is this common on immobilizer equipped cars?

Car is a 2001 audi a6 2.7t mt6, flash 4b0907551aa, original ecu contents (to my knowledge) with an active, working immobilizer. After the flash (flashed over to an m-box) Everything appears to be ok, but I'd like to reduce the amount of drama next time. Attached are the original ecu read, as well as my log from nefmoto.

A few additional details:

Yes, I connected and flashed via OBD
Yes, I had galletto (and a spare IMMO defeated ecu) ready for boot mode in case of a failed flash\
Yes, I had the car connected to an external power supply charging @ 13.5 volts.

Thanks for any help you can give me. Sorry for the extremely long post, but I figured better to be informative.