I'm using an AT&T locked iPhone 3G (8GB) for my Celcom network in Malaysia.

I have managed to solve it via this process flow

Method (1)
After installing the yellowsn0w 0.9.5..
- 3G and Data Roaming off
- Reboot
- Airplane Mode On
- Reset Network Settings
- Airplane Mode Off (...searching...)
- Voila! Got my Celcom signal..!!!

So far, its quite stable. In fact the 3G signal is much better than before (when I use turbosim solution on FW 2.1)

Earlier I have tried the method of using the "yellowsn0w -c" etc command but it doesn't work.

Thanks to Dev Team!!
I have been monitoring this progress since I bought my iPhone 3G in August 2008.

Once you have successfully unlocked it, and when you tried to reboot or switch off your iPhone, the ONLY thing that you need to do is this -->

Step 1 - Switch ON Airplane Mode (wait 5-10 seconds)
Step 2 - Switch OFF Airplane Mode

- Once you see the "Searching" Indicator, most probably you will get the carrier signal back.
- Otherwise, repeat Step (1) and (2).

Try this Method (2) of Method (1) does not work..

Method (2)
After installing the yellowsn0w 0.9.5..
- 3G and Data Roaming off
- Use mobile terminal --> yellowsn0w -r
- Reboot
- Airplane Mode On
- Reset Network Settings
- Airplane Mode Off (...searching...)

Just unlocked a 3G iPhone from UK.
Its working with my DiGi Simcard.
What I did was unlock the phone with my DiGi Sim inside.
Taking the Sim in and out after that until the phone can get DiGi signal. Thats all..

Originally Posted by ltcchuan

Just unlocked a 3G iPhone from UK.
Its working with my DiGi Simcard.
What I did was unlock the phone with my DiGi Sim inside.
Taking the Sim in and out after that until the phone can get DiGi signal. Thats all..

Thanks for your update.
Could you please share with the rest of the members with a more detailed steps.
Like, did you reboot or use mobile terminal command etc?

yellowsn0w 0.9.6 solved all the hassle of the above process flow.
Install the 0.9.6 and reboot.... voila!! Instantly got the signal.

everything work fine for me, it just my bluetooth somehow can't discoverable, it there any way to solve it.
i'm using 02 U.K locked IPhone 3g(16g) for my maxis network in malaysia.