The only thing that is different is that I now have Linux running in chroot.
My solution is to start over.
Luckily I can still adb recovery boot into TWRP, because I am still on the 4.5.3 version of the software.
First, I download a newer Amazon OS on to the tablet. I found download links on XDA. In fact you can stop reading now and try to follow the XDA instructions.
Anyway here is what I did:
Look for my next post, which will likely be called Corrupted the Kindle Fire HD 6 4th Generation (AGAIN!). BTW I am doing all this because I essentially got the new 16 GB tablet for $40 off Amazon.
Oops, I almost forgot that I need to turn off automatic updates. Here's a how-to on YouTube.