Same problem.
My phone is only 3 months out of warranty, and it worked great until about a month ago. Now it reboots about a dozen times a day, and is completely useless.
Here's everything I've done so far, and none of it has had any effect:
- bought a replacement battery
- factory reset (tried this 4 times)
- formatted the SD card
- put in a brand new SD card, and then another
- ran the phone without an SD card
- ran the phone without a SIM card
- put a folded chunk of paper on top of the battery in case the battery is slipping (unlikely)
- rooted the phone and installed the Cyanogen mod
None of this has made the slightest bit of difference. The phone still reboots every few minutes. Since I'm out of warranty, is looks like there isn't a thing I can do. I've read that I can send it to HTC for repair, but I'll have to pay shipping both ways in addition to a $40 charge just for them to look at it. At that point if it needs parts and labor the fix will end up costing me more than the phone did when it was brand new - and it's only a year old.
At this point I'm about to just sell the phone on eBay for parts, but hate the idea of trashing it after only a year of light use. I love this phone when it's working, but clearly the hardware is seriously flawed if it dies after just 15 months.
Other than scrapping it, what else can I do? I'd love to get a Nexus One or the new version of the MyTouch, but I'm really reluctant to get another piece of HTC hardware now.
As much as I hate the idea, I'm about to ditch Tmobile altogether and get an iPhone just because I need a stable smartphone.
Any suggestions would be greatly appreciated.