After I flash *any* factory image it goes back to my 5.0 lockscreen topic

I am pretty sure this one is a doozy, or that I am missing something very simple... you know, one or the other ;)
First the facts: 2012 Wifi Nexus 7 running 5.0, stock rom, unlocked bootloader - nothing fancy about it.

Some background: I've been having a constant reboot issue for a while now... not quite a bootloop, as it allows me to enter my screenlock and even open the settings menu before suddenly rebooting again (at random intervals). Any changes I make in that time are lost upon reboot and it takes me right back to my 5.0 lockscreen (even if I disabled it the last time it was booted) - Same thing happens if I uninstall any apps, they are there when I reboot again.

I am able to see my device in both fastboot and recovery.

I've tried a factory reset from the Settings menu - no go, right back to my 5.0 lockscreen.
I've tried to reset from recovery - no go, right back to my 5.0 lockscreen.
I reflashed the image from the bootloader - no go, right back to my 5.0 lockscreen.
I flashed 4.4.4 - no go, right back to my 5.0 lockscreen.
I flashed 4.4.2 - no go, right back to my 5.0 lockscreen.
I flashed 5.0.2 and the same thing happened - no go, right back to my 5.0 lockscreen. (I was able to check About Tablet... no changes there either)
same thing with Safe Mode- no go, right back to my 5.0 lockscreen.

Wug's toolkit failed on me when I tried that, after the bootloader and boot image failed I got an out of memory error. (tried a couple versions here, Jelly bean actually forced fastboot to close on me)

I did a Remote Erase Request from Android Device Manager, it did not work either.

This is sounding like a hardware issue, right? Anything I can do about that if so?