Default help | sghm919 rom 4.3 and no signal fix

hey, i need a room for sgh-m919, official of samsung, if I flash a rom than the imei is being changed, can you give me a filethat fixing it after?
thx!
btw - it doesn't matter to me what rom it will be (country) but i need an official one
i think it need to be i another forum but i new here