There were various revisions to the ECU s/w..I've not climbed a learning curve to proffer any advice on this (yet!

)..
I know when the tuners were stuggling with my Celtic tune they re-flashed it to a later update of the 20i ECU firmware as a starting point.
I've just loaded ISTA/P so will have a look at that..I think you need to get an update from a BMW factory server..but will check..