As you might remember, HTC's Touch Diamond Windows Mobile smartphone is supporting triband GSM/GPRS/EDGE at 900/1800/1900 MHz as well as dualband UMTS/HSDPA/HSUPA at 900/2100 MHz only which makes it a smartphone with a strong focus on the European/Asian markets. While inbound roamers can use the 1900 MHz network during its visit of the U.S and Canada, the HTC Touch Diamond, as available today, isn't a real option for Americans since the important 850 MHz band, as used by AT&T wireless. Now some clever developers at Xda-developers.com found a way to enable the missing 850 MHz band on the HTC Touch Diamond to make it a quadband GSM/GPRS/EDGE device.

The workaround requires flashing a custom radio firmware onto the HTC Touch Diamond which means it's not an officially supported way to get a Touch Diamond quadband 2.5G but if you are in need of quadband GSM support, it might be an interesting alternative to waiting for an official Touch Diamond release in the U.S.

At this point it's not clear why HTC has locked down the GSM 850 capabilities. It might be either due to some market protection for U.S. carriers or it's a licensing thing between HTC and Qualcomm but nevertheless, it's now possible to get the 850 MHz band working and even better - it's confirmed to work. However, so far the UMTS/HSDPA/HSUPA part wasn't unlocked and this fix only provides quadband GSM capabilities, not quadband UMTS capabilities.

However - as always - please keep in mind that you do the Radio upgrade on your own risk. Neither the::unwired nor Xda-developers.com takes any responsibility.

Cheers ~ Arne