Configure Australian Phone to work on US Network I have an HTC Desire HD (unlocked) purchased in Australia, currently operating on a T-Mobile network but I am not getting any data service. I purchased an activation kit from Amazon and the $30/mth unlimited data package from Walmart. Text and voice are working fine, but I am not receiving any data.

The data plan is a 4g plan but I assumed that would also include 3G for those without 4G phones.

On the phone settings, T-Mobile is listed under settings > Wireless &amp; networks > mobile networks > Network Operators. When I select Network Operators > Select Automatically it flashes up a message "registered on network".

Is there something I must do to get my phone to work here? OS = Gingerbread.
You can't. The "international" version of the HTC Desire HD is not hardware compatible with T-Mobile USA's 3G frequency bands. The phone's antennas support HSPA on the 900 and 2100 MHz frequencies (the North American GSM variants should work, though: source), and software settings will not have any effect on this. T-Mobile's 3G network uses:


850 MHz: Acquired via a roaming agreement as part of the failed AT&amp;T merger
1700/2100 MHz AWS: the device must support both of these frequencies to work because the 1700 band is used for uplink and the 2100 band is used for downlink.
1900 MHz


As you can see, these do not line up (excepting half of the AWS band, which is not sufficient). You'll need a new phone if you want 3G service. See Can I use my device on a different carrier? for suggestions on how to determine which phones will work.