Here’s the easy tips on how to restore BMW EWS system.
1 take another Ews and write in yours.
2 restore to factory settings (ews editor software can do it)
3 instal to car and code with Ista-P.
4 take out from car and make new key(s).
5 instal to car and make Ews-Dde, Dme synchronisation (ista-d, Launch, Autel and so on….)
6 Bingo car is start.
AK90 is the best and cheapest to read EWS.
Soldering would be the safest way.
make sure you select the right chip type as well and no external power on the AK90.