i sent a couple of unlocked iphones back to malaysia, but only one out of the 3 main GSM companies are able to be used. why is that? does anybody know or can help me?

I read somewhere that iPhones do have some problems on Maxis network.

so there's no way i can use it or get it to work over there?

there's something wrong with maxis's base transmission , but someone of maxis said that they will get it repaired by this year . so maybe we should use with other carrier temporarily.

actually celcom works too. just some simcard issues. you either request a 64kb simcard or do this workaround

Okay, 1st step put atnt sim card (or any working simcard, digi, maxis) n power on.. Wait until it got some signal bar / no service display..

2. Go to setting, carrier. If will search for network. (if no carier show, go back home and wait a while). wait till all 3 network found.

3. Press power buttonto put iphone on standy .

4. Replace the simcard with celcom.

5. Press power button. You will see the network list. Choose celcom and press home button..

credit - aneip
source: http://www.irwan.biz/iphone-hack-succeed/#comments

While roaming in Malaysia, mine was able to use Maxis & Digi without any problem.

Duirng that time, I was on ver 1.02 now have updated to 1.1.1.

This will provide you with additional information:

http://www.hackint0sh.org/forum/showthread.php?t=6327

could there be any other ways to get calls?