I have been noticing with CAS4, when ever I add a key, usually customer original key...will stop working, or comfort acces and remote functions will not work.
Is this the reason autohex always recommends removing CAS4 reading it by EPROM dump, make a key for EWS5 not active.
For active, they say pull ISN from DME, then by OBD is fine.
Just wondering because lately I have always had to give customers 2 new keys, and just consider there original key a waste, not worth trouble to unlock the key.