Had to swap the motherboard after the memory went bad (possibly from an update)
My tablet's emmc became corrupt after an update. It was an OTA provided by Google, and apparently I'm not the only person affected by it. My tablet was on 5.0.2 for a while, and then one day it just started boot looping.
I'm not a power user, but I did everything I could through the software and OS, as well as any fastboot and recovery settings. I tried a couple different tools to try to un-softlock it as well, but nothing worked. The step that finally convinced me it was a hardware issue is when I could not wipe the cache partition.
I was out of warranty, didn't buy it through Google (so no help from them) and similar stories said Asus wanted 200 bucks to fix the issue, which is alarmingly close to the tablet's initial purchase price.
The teardown provided by iFixit led me to open up the tamer before I even considered fixing it. It was actually months later that I saw I could buy a replacement board.
My roommate had some iFixit tools I used to take the case apart, and fortunately after that it's pretty much just some screws and ribbon cables. It was actually pretty easy for me, and while I took a lot of electronics apart as a kid, I didn't really put many back together again.
First, know that a couple of the ribbons you actually pull up from the motherboard, not out of a slot. Specifically one of the cables that crosses over the battery, and a cable coming from below the battery (it's the only cable that is composed of multiple colored wires and not a ribbon and has a black connector).
Also, the cable connecting the other bottom board (the one with the USB port on it) to the motherboard needs to have a white plastic bit clamped down on the connector after the ribbon is plugged into it. I didn't notice this when I first reassembled it, and didn't know anything was wrong until it wouldn't connect to my PC via USB and wouldn't automatically change the screen to landscape when turned.
Also, if you don't have the plastic separation tools that iFixit provides (or similar) consider using a guitar pick or credit card as well as your finger nails. Just don't get impatient and use a flathead screwdriver like I did and get little dings and scrapes in the case.