"After over a year of reliable use, the recent Lollipop update cause some odd behaviour from my N7 2013... First after a few days, the auto rotate stops working (a reboot usually gets it back, but not always), then after a few days it locks up (no touch screen) and a hard power reset gets stuck at the Google logo..
After a couple of these I down graded to KK, complete wipe... No problems... Now with 5.0.2 I thought I'd try Lollipop again... It took about a week, and it started doing it again.
The really weird thing is, once it gets stuck in the Google logo "can't boot" (I can go into the boot menu, but won't go into recovery - gets stuck on Google again), there's a way I can always get it working. Hard power off, open it up, unclip and reseat the touchscreen cable (the thinner of the two cables across the back of the battery)... Then it's be straight back up and running perfectly.
I suspect that something in the boot sequence is trying to initialise the touch screen, and not handling an error state properly, causing it to hang... Fix the cable and it's fine again.
I'll replace the cable at some point I'm sure."
I've had this issue for two years. Every few months I'd pick up the table and see if there was anything new I could try to get it back. This is the first time I've seen to try this, and your comment that has gotten my Nexus 7 back to the world of the living. I'm truly eternally grateful.