All you need to do is download a ROM called "Khuanchai_IF1_21001_UL_PP6". And go to Start> Setting> Personal> open the Phone icon> go to the last tab called More, then click on Band Selection. Get the setting. Change it from Automatic to GSM 900/1800. Thats it. If it doesn't work then change to next frequency and so on, because my network works with GSM 900/1800. Good luck.
If you can't change the frequency I will argue you to install the mentioned ROM. because I tried with other ROM they didn't let my change the Band Settings.
Let me know if it really fixed yours.
Edited by k7420, 17 May 2011 - 04:12 AM.