Yeah 3G is lil bit unstable. Its shows 3G bt most of time it keep stucked with edge. Replace modem.img file with stock or any other working rom. Its modem.img file is smthng like modem_3g_n.img. Rename stock modem.img and replace it. Change permissions and reboot. Enjoy.
renamed, replaced the modem, 3g-does not work (. can zip. you need to survive?