I read your post and it seemed like we have similar issues. I let my phone repeat the start up process on and on. It seems like a overheating issue cause when I leave the battery detached from the phone and it cools down, it will boot up normally (after multiple boot ups). Then it will hang again after a few seconds. This happened multiple times.
So I just repeated the process and tried to boot into safe mode before it restarted again. I eventually managed to boot into safe mode and copied the folders from the phone to the SD card. Needless to say, after transferring, any attempts to boot back normally outside of safe mode was unsuccessful.