How to troubleshoot this condition of recurrent restarts? State of my OnePlus2 phone after Tech2 support session, troubleshooted in the thread How to login to resetted phone when verified password not accepted? 
I am thinking what to do before my second tech 2 support session is taking place. 
The tech support did not manage to resolve the original case completely because time ended of the session. 


Phone starts. Welcome screen. It does not accept all inputs (something wrong in the system). Sometimes, it restarts itself during the welcome session and goes back to welcome. If it goes to the desktop view, it restarts itself in few minutes, and goes back to welcome. 


I think this condition can be only for OO support but not sure. 
Maybe, there is something which could be done, because now, access to the phone frontend. 

Phone: OnePlus 2
OS: 3.1 OO, Android 6
In the recovery mode, cleaned all memory. Reinstalled bootloader. No effect on the phenomenon. Finally, money back from warranty because most likely a software issue in OO itself. Two sessions with OO Tech support.