I have an HTC Desire for 6 months now. Before 2 months started overheating when I was using the browser for surfing on mobile network (not wifi), so I contact HTC and they suggested sending it for service. The phone was unrooted and so they send it back to me after 3 days with a new mainboard. After this entire stressful situation I was very precocious with the phone, when it starts to heat I just stop use it. Before few weeks when the rumor that we will not take the update break threw I used unrevoked 3 to root it but I never used a custom rom.
Until yesterday the phone was working just fine, never overheated, but during the usage of desire