[Kindle Fire HDX 7" & 8.9" Q&A, Help & Troubleshoot] fufu508:
Open this to see history leading to the solution:

( I moved my question here into the help thread, pasted below from my post at [HOW TO] Unbrick Kindle Fire HDX (QHUSB_BULK) with firmware <=1314.3.2.6 by ONYXis)

Thanks ONYXis for these instructions. Do you have a copy of the archive linked to in your original post?

Your link doesn't work anymore (file not found).

Does anybody else have a copy of this archive? Hi @Davey126 I see you are still active (literally) on this device and participated in the thread above. I'm hoping you can help clarify what files are needed and where to get them.

ONYXis included the following screen shot showing a "fw" folder with what appear to be the needed files for the flash operation:

[IMG="Screen shot of files"]https://img.xda-cdn.com/bEb_WUHOSZzW8yPvq3C4rD7Mw_k=/https%3A%2F%2Fimg.xda-cdn.com%2FY85XckuEYxdb_0UBIEw4sUQwWeA%3D%2Fhttps%253A%252F%252Fimg.xda-cdn.com%252Fh-t2q2yyRwFLy6vTRtwpgJBr9l0%253D%252Fhttps%25253A%25252F%25252Fimg.xda-cdn.com%25252F3lxQh4Q3lKTwLvliPI8fTBVVDBM%25253D%25252Fhttps%2525253A%2525252F%2525252Fimg.xda-cdn.com%2525252F5v8R-6V1Cnb3n1pLFmaObTlHbG0%2525253D%2525252Fhttps%252525253A%252525252F%252525252Fimg.xda-cdn.com%252525252F_CZVVchW5l_ml6IvUQm8WRklx3o%252525253D%252525252Fhttp%25252525253A%25252525252F%25252525252Fi.imgur.com%25252525252FxYHj4aA.png[/IMG]

After much digging through posts here on xdadevelopers, and with the use of a "factory/fastboot" cable , I was able to get my tab to boot into Qualcomm QDLoader 9008 mode and MiFlash 2015.10.28.0 sees it.

(post #50 Thanks neoroid!)

Now, I just need the fw folder from the archive mentioned in the [HOWTO] post at the link above..

Some background:

Used KFHDX Toolkit v0.94 (towelroot, supersu, safestrap)

Installed TWRP 2.8.7.0

Installed cm-13.0-20160219-UNOFFICIAL-thor.zip

thor-bootloader-13.3.2.3.2_upgrade.zip

It is now only booting with gray Kindle logo.

I ended up losing access to recovery and bootloader. The adb connectivity works but adb devices returns "unauthorized".

If I do nothing it continues on and attempts to boot Cyanogenmod 13, sitting at its boot splash screen.

Sometime last year (sometime after the March backup taken above) I managed to brick it, trying to reinstall Cyanogenmod 13 (or restore its TWRP backup), if I recall correctly.

2017-Dec-17 - update: My Kindle is un-bricked!

Please see details in subsequent posts in this thread.

I will summarize them here after I get the bootloader unlocked Done apparently already! My (soft) brick seems to have been due to broken recovery (existing TWRP corrupted somehow) and/or bad volume control buttons.

The original purpose of this thread has been accomplished, now to get a new OS image installed. Done!

Summary:

1. It looks like my tablet possibly could have had a working recovery but I won't know since the volume buttons on my Fire HDX 7 (Thor) don't work, hence no Power+Vol-up, no Power+Vol-down to enter recovery and fastboot modes respectively.

2. The cable with the design mentioned hereand here allowed my tablet to boot and with MiFlash 2015.10.28.0 I was able to push onto the tablet the latest recovery with special instruction to load it on next boot (bypassing the need for pushing the volume buttons!) thanks again [MENTION=5828306]draxie[/MENTION] for the "fw" archive! I have made an updated fw.7z with the Thor aboot and image for TWRP 3.1.1-1 and the setting to launch that on next boot.

3. With a working TWRP in place (which the tablet booted into everytime after flashing in step 2) I was able to sideload the files mentioned in [ROM][7.1.2] AospExtended [19/11/2017], specifically:

- Aosp Extended for Thor

- OpenGapps 7.1 (PICO)

- Magisk 14.0

I tried stock OpenGapps but it wouldn't fit, gave error 70 during attempted sideload.

Result:

This is now the fastest tablet I own! So much faster than stock.

If you have read this far, I hopefully cay pay it forward to anyone else with similar Thor situation.

PM me if you want a copy of my Thor-specific fw archive and/or a copy of MiFlash 2015.10.28.0.