Thanks Scoobio, I did try that too. So far I have successfully installed 3 versions of bootloader (FFF 1.4a, FFF with yellow triangle, and also stock from Amazon). All three install successfully. Unfortunately all three have the same symptoms. I am able to execute fastboot commands to flash images, getvar, etc, etc, and they complete successfully. However anytime I "ask" or "let" the bootloader try to boot system or recovery it hangs. FFF 1.4a hangs, previous "yellow triangle" version of FFF hangs, stock also hangs - always at the same point. The screen never flashes like it does when the recovery or kernel first loads. So I don't think its making it that far.
I've tried with factory cable, regular usb, no usb at all. Always hangs on boot. I also tried running KFU in Windows (same problems), SoupKit (same problems), and FireKit (same problems). Last thing I tried was usb_fix_parts_and_install_fff_twrp. It also ran successfully but still same problem.
At this point I don't care so much about fixing the kindle as much as solving the riddle. I'd like to figure this out just so I know...you know I can't let the machine win. So I'm wondering if it could be bad memory blocks or something else missing...will update if i discover anything further. Any ideas greatly appreciated.
Oh and...I am able to reset bootmode back to normal or recovery or fastboot...always completes the command successfully but never makes a difference.