[ONE Q&A, Help & Troubleshooting] oski131:
Hi everyone, i know the title seems like it's just a trival matter, but trust me it's not.

The phone was bought new in August of last year (2015).

The story so far: I've been using sultanxda ROM for over 6 months without any issues, but i decided to test a different ROM, so i downloaded Darkobas rom and GAPPS, the ROM and Gapps installed fine but when i started the device and i was doing the initial configuration the phone rebooted by itself. It happened about 3/4 times and after that the phone had entered a bootloop. I tried to reflash the ROM and gapps, but the phone was restarting during the flash in TWRP. I decided to go stock Cyanogen OS, so i did a clean fastboot install of cyanogen OS. Everything went well the phone was working fine, but a few hours after installation the phone was randomly rebooting again, i decided i'll live with it and wait and see if it goes away by itself.

The phone was rebooting 2/3 times a day, during different acitivities so it was hard to pinpoint what might the issue be (even when locked in my pocket with all apps killed). After a few days of usage it just went straight to bootloop, after that i had issues to even install a rom (even via fastboot), because it would install everything fine and then it wouldn't start properly and would be in a bootloop (straight after installation).

I also tried the Bacon Root Toolkit installation as well as formatting everything and wiping everything. But even with the usage of Bacon Root Toolkit the random reboots happened.

So i installed an older TWRP recovery, i wiped everything re-formatted the phone to F2FS (was EXT 4 b4) and installed a F2FS compatible ROM (can't remember which one), after that installation everything seemed to work fine, but after a day or so the random reboots came back to haunt me again. So i reformatted the phone to EXT-4 again, installed stock cyanogenmod via fastboot (the 4.4.2 version), and updated it to 6.0.1 via OTA (during the course of a day or so, but even when the phone was on 4.4.2 i had a random reboot once), and the reboots returned ( i tried many different solutions, even the command line in TWRP "make_ext4fs /dev/block/mmcblk0p15"). I had NO IDEA what might be causing them but i thought that maybe the processor is ****ed and it's overheating, i returned to sultanxda rom (with the underclock to 1957 mHz).

After returning the phone booted correctly after a clean install via TWRP, but now it's rebooting again, and sometimes it happens 4/5 times in a ROW, sometimes it doesnt even reboot, but goes to black screen and I have to push the power button for 6 + seconds for it to reboot.

I've tried the stability test, or running antutu a few times in a row to verify if maybe it's the processor's/RAM's fault, but the phone didn't care, it rebooted randomly (sometimes 6/7 antutu runs in a row and nothing happened, sometimes rebooting in my pocket with all apps shut down). I've tried different launchers/messing with WiFi options/turning off the proximity check/turning off the trust agents nothing seems to make a difference. At this point I'm at a loss of what to do so i came here to ask for any advice. Is there any way to check if the phones internal memory is corrupted in some way ? I've tried searching for some apps but nothing turned out.