Default [Q] samsung gt-n7105

Hi i have a samsung note2 (gt-n7105) the hong kong version i wanted to know if there is a way to change everything to the english software as im have problems with signal witch i have been told could be the modem files but i do not know how to change them i have managed to root my phone from help from your forums i have been told that the modem file could make the signal strenth to be bad and give call drops out and not registed on network

i have all ready checked the phone is not blacklisted

If any one can help i wouls be very gratefull