Hello everyone

I am having some issues with my n900 and I need your help, around a week ago my n900 usb port got broken and it came off the device, I took it to a friend who fixes cellphones and he resoldered the usb back again, its the second time he fixes it for me, the first time there were no issues, so when he put it back together and turned it on a reboot loop started and it kept going for a couple minutes then it finaly turned on, for a couple hours it was working just fine but then out of a sudden it rebooted again and started with the reboot loop again, this has been happening since then, i did some research around and it apears that flashing sometimes helps, so i flashed the device, vanilla first and combined latter as it says on the wiki, it worked just for a couple hours and then it rebooted again, the only diference is that now it doesnt loops most of the times, these reboots happen at all times no matter what i am doing with the device, some times it also happens when its charging, i havent seen it reboot when its on stand by.
I am takeing it back to my friend to check if theres anything wrong with the hardware.

Can you please help me to find out what is the reason for these reboots?

I installed HealthCheck and it shows:
Boot Reason:
sw_rst

Please help, I really like my n900 and dont want to change it for an other cellphone.

Thanks.