[HD2 General] motoi_bogdan:
OK, after some long time away from phone hacking and stuff like this, i'm back.

Let me explain my latest progress with this problem. Some time ago, thanks to atjong1, who donated me some broken hd2 parts (mainly the motherboard and flex cable assemblies) i continued with reheating experiments. I combined this motherboard with some other hd2 parts (display+casing). My parts were previously tested and confirmed to work ok.

So i started the phone using the motherboard just as i received it.

It started, booted and allowed me to perform some basic tasks, then it locked up and the more familiar pattern emerged: freezes, restarts etc.

So i begun heating up the cpu using my smd rework station. Based on previous experience, i've begun at 230-240 degrees and checked the progress after each attempt. After some 8-9 attempts and also after reaching 320 degrees, the problem wasn't fixed. Damned thing just kept up rebooting by itself. There were only some small variations in the temperature point at witch the phone begun restarting but nothing notable.

I've used the motherboard with the camera module and flex cable, just as i received them. But at one point, after one failed heating session i accidentally swapped the original flex cable that came with the motherboard with another one laying on my desk (from another hd2). The funny thing is that after this, the board worked ok and never restarted. I tested it for some hours and all was ok. I then switched back to the original flex cable/camera module and the problem reappeared.

So, for the first time, i've noticed a connection between the motherboard and camera module as far as these problems (restarts). I cannot find any reasonable cause or connection between the 2 boards (motherboard, camera board) in such way that the camera board can produce or worsen the thermal proprieties of the qualcomm chip. Yet the proof was undeniable. In that particular case, the phone kept restarting even after a successful heat up. So, it seems that the flex cable and/or the smaller board can contribute to this problem in a way i cannot yet describe. I believe this is a rare scenario, but basic troubleshooting tips for this problem remain the same:

1. you notice the problem and by basic measurements you determine that is thermal related.

2. disassemble the phone.

3. heat up the cpu using specialised tools (smd rework station would be ideal)

3. remove the camera flex cable from the motherboard. leave only the buttons flex cable and the display, when you are testing.

4. start the phone using this configuration (without camera module attached to the motherboard) and test for cpu stability or reboots.

5. if all is ok, reattach the camera module. If the phone starts to freeze or restarts by its own, you may have a faulty module. If the phone works, you have successfully solved the problem.

1. a few things a need to repeat and the usual warnings :

1. don't try to over improvise about heating up the cpu. A gas/electric oven (not microwave one!!) could work but even this will reduce your chances of success compared to using dedicated equipment. Don't heat the cpu with a naked flame, hot iron or stuff like these.

2. even when done properly, you cannot be sure it will work, in fact, previous experiences around this topic say something about a 50-50 chance.

3. if heating process fails, the phone WILL die. Period. It will never work again.

4. don't use the method described in the first post (cpu heatsink) to repair a restarting phone or one that freezes. It will not solve the original problem, that guide will help only after you reheat the cpu, in preventing this problem for happening again.