If you look at the specifications of the HTC Touch Diamond, you'll notice that the GSM radio supports 900/1800/1900MHz, which is great for use in most countries in Europe and Asia. If you travel to the US often though, a quad-band radio with the 850MHz frequency can come in handy (it's a bonus--tri-band phones can already roam in the US). In a surprising move, the Diamond's latest ROM update gives the handheld that fourth band, an unlocking of a hidden feature of sorts. The last time we remember something like that happening from HTC was when it was still selling its products under the Dopod brand and activated GPS navigation in the D810 after first selling it without that feature advertised.
According to user reports from message boards and other enthusiast sites, some have noticed performance improvement in the device after the update, too. That's another bonus point for current Diamond users. This new ROM is already available for Hong Kong customers. According to HTC Asia, the rest of us should be able to download it in early/mid-August.
Via WMExperts