replace a CID52 with a CID49

[jsaren]

but my friend wrote cid49 farfirm files to my cid51 w710i yestoday.

[cibo]

your phone has - OTP CID and EROM CID.
EROM CID you can upgrade for example from 49>52.
but OTP CID will stay at 49 only EROM CID is changing.
then you can with service cable rollback your cid to OTP VERSION.