[JASJAR, XDA Exec, MDA Pro ROM Development] cyberjak:
this is an actual common problem possibly residing to a specific batch load or maybe more. the problem will get worse and in short it's not a battery it's a mainboard problem with a sensor or a part that becomes hypersensative to heat. I think it's part of the same circuit that shuts the device down if the cpu or battery overheats but I can't proove it yet. I've had 2 of these phones so far. 1 3 got t-mobile t swap for an mda vario 2 at the time as the phone wouldn't stay stable for more then a few minutes. same result with 2 like 4 like replacements they sent me. ifinally said enough I want the closest thing tech spec wise to it. the 2nd one was my wifes which she barely used now that shes moved on to a different phone I've started playing a bit with it as it's over 12 months old. and I put it back into the box and up on a shelf as soon as it started doing the rebooting thing like the first one. NO WONDER ORANGE START DISCONTINUING IT AS WELL DID T-MOBILE UK.

UPDATED :

After reading a few of the posts aftr mine, I set out on a mission to determine the more exact reason for this cause. I found the unlike most mobile e.g: sony, lg, nokia etc. this phone would nout power on from the mains adapter without the battery. I figured initially it must have been the manufacture thinking this is not a laptop and the mains adaptr was intendd to charge batteries and then run the device. this also prevents data loss or file system corruption incase your mains charger comes loose from the device while playing. however I found that by putting my finger (when your finger tips are lightly moist and conductive) over the battery terminals on the device it would infact power on and work. now in light of this there are 6 terminals to make conduct with the battery the outter 2 on each extreme end are your + and - . the 2 inner ones are likely then to be battery voltage sensor and battery temprature.

so I said great way to test a theory. I unplugged the mains charger and started downloading files from my pc to the memory card over wireless. this of coarse caused the battery and the device to heat up very quickly. within about 10 minutes it did as expected and shut off. then when pressing the power button could not make it back to the main today screen either it would shut off on the windows mobile splash screen OR it would shut off during the first splash at bootloader.

I then removed the now very warm battery and put my finger on the battery terminals making sure the 2 center pins were touching my finger. voila th device powered on and booted up just fine. I then went back to doing file transfers and it never shut off on me again as lon as I held my finger on the battery terminals. in short I fooled it into thinking the battery was there but but that the temprature was fine. wm6.1 from ranji's 7.1 could tell there was no bettery to charge but the temp sensor was fooled. conclusion: the reason 2 replacement handsets in the past sent to me by t-mobile conitune to fail was not infact an internal problem that was main board related it was the battery incorrectly sending wrong temp info or a faulty battery that was getting to hot and the manufactures own safty device was shutting the device down to cool off the battery. this would be why in the past I would be able to just leave it off and eventallly it would work again. I felt like such a fool but at the same time I felt good that I got 1 traded for a vario and that now all I need to do to fix my mda pro is t get a new battery. I am man enough as you can tell to say wheni was wrong and I was. in light of this new info I would recommend the device to others but if you start getting random shut downs and turn offs during internet over wireless or gprs and the device is wamr ask your provider for a new battery or replace it yourself maybe even with a larger capacity one as it will likely resolve your problem. I know there are other posts i've done about this subject and I HOPE that those that have read them read this update as it applies to all htc universals regardless what branding they fall under.

enjoy in knowing new things

cj