Which tool for CAS 3++ key programming? How to do?

Topic:how to program Key for BMW  CAS 3++

1. Use AVDI to program key for CAS 3++

Normally we get these and then remove and backup on the bench before downgrading and programming a key through OBD with AVDI with 13.5v charger etc.

Cons: obviously don’t like downgrading as potential issues and also removes the security aspect in the car.

2. Use CGDI BMW Programmer to program key for CAS3++

It is possible to bypass the downgrade by reading the flash and EEPROM on the bench and then loading it into tango and programming key through that.

It's how I used to do 9389115 before it was doable by OBD. I used CGDI BMW not Tango to write the key, though. Once downgraded, you can always reflash in a couple of minutes.

3. Use Tango to program key for CAS3++

If we talking about spare key then, of course, read EEPROM on the bench is enough (working key required to decrypt ISN). If all keys lost still need downgrade or need cas eeprom + ISN from DME
Tango always prompt to write new EEPROM to CAS after key programming but you don't have to do it, unless you program new key on already used position.
Question:
I tried this today with a working key and it doesn't work. Old key works fine, but the new one just doesn't bring the dash on? In the end, I downgraded CAS & then programmed through OBD and worked fine (obviously having a backup first.
I've tried it on 3 cars though so don't think it's my files, cause I always verify the read with VVDI prog & Tango detects it as a cas3++. It must be my keys.
Answer: I do duplicates the same way, but I use the Xhorse VVDI2 programmer.

4. Program key for CAS3++ without downgrading:

You can read EEPROM on cas3+ or cas3/ista-p, then use a programmer to make key with EEPROM file. that's how I do keys when I don't downgrade. I don't write back to CAS, I choose new key position.
Thanks.

http://blog.obdexpress.co.uk/2019/11/20/how-to-program-key-for-cas-via-obd/