mobile

I downgraded, then upgraded to to 14.4.5.2 successfully. Rooted successfully. Had trouble getting Google Play to work. At some point after trying numerous avenues, I rebooted, and got stuck at the animated bootscreen. Not the grey one.

I have ADB access still.

I tried the factory reset from the recovery screen on the kindle (unfortunately before checking this forum). I never used/installed safestrap at all, and have no experience with it.
From there, I've tried ghettoroot, numerous ADB processes, and even the KFHDX toolkit.
Ghettoroot seems to work, but halts at the end with a string of [DEBUG] headers and I can't issue the final 2 commands.
The device has access to ADB, and seemingly to SU, and appears to be rooted.
I've followed the other unbrick thread and get stuck with the permissions denied fault.
I tried fixing it through fastboot, but I cannot find a fastboot driver that will work with Windows 8.1, even after fully installing Android SDK and going through the Amazon developer's page with instructions for both.

Is there any way to recover this with ADB access that I haven't explored yet? If this thing is completely tits-up while out of warranty will Amazon fix it for a fee?
If there is a simple way to re-image it though ADB I'm all ears.

I have exhaustively explored this forum and cannot find anything that has had any success. Been at it since 10AM and it's now almost 8PM.
If there is a way to provide you logs, let me know and I'll do it.