Short version:
- Normal startup: Stuck at Google screen.
- Unlock bootloader: Stuck at the selection.
- Recovery mode: Stuck at Google screen.
Long version
My Nexus 7 (2013) had always been fine, and I liked stock Android very much, thus saw no need to unlock the bootloader. When the 5.1 OTA came, I updated my N7 and it started crashing and restarting on its own. One day, it restarted again and got stuck at the Google screen.
Of course, the first thing I did was to get the Nexus Root Toolkit, and tried flashing stock ROM. Of course, it didn't work since it was OEM locked. When I tried to unlock the bootloader, I was prompted with the screen asking if I want to unlock and wipe all data. I selected unlock and pressed the power button. Then it froze (I left it for 8 hours, plugged it into a power outlet).
The next logical thing to do was to start recovery mode in the fastboot to do a factory reset, except it simply switched to the Google screen and was stuck there.
I've read many articles, but it's always one of the three issues I have. They often refer to using a method that involves an area where it's affected by the other problems.
How to recover from this situation?