[Kindle Fire HDX 7" & 8.9" Q&A, Help & Troubleshoot] Andromeda2145:
History:

This was a virgin stock rom'd kindle that just didn't boot one day at the end of last November. The battery was showing signs of degradation, i.e. false/flaky battery life, and I think random restarts! My guess is that it was most likely updating when something went wrong.

I cannot be sure what firmware it was on or upgrading to, but at the same time that it happened, around the 22/10/2017, I could only manually download update-kindle-14.4.5.5_user_455004320.bin from amazon. But my daughters identical KFAPWI took the 4.5.5.3 update on the 17/10/2017.

So I'm going to take a stab, and say it most likely on 4.5.5.2.:fingers-crossed:

At one point I had the grey boot logo only, but after pressing too many combinations, getting drunk and falling asleep, it now does nothing:crying:. It does not connect to the pc at all, despite my persistence holding down the power button for far too long, and even using a factory cable - have got drivers previously installed from rooting/buggering/fixing another kindle, both standard and qbulk. Using a DVM meter on the battery yields the correct voltage for both cells too...

I'm better with the down and dirty hardware side of things, so I have taken the less-than-direct direct emmc access root by Ivan_nik in his post her on XDA: https://xdaforums.com/kindle-fire-hdx/general/direct-emmc-access-t3249534 and have success in reading the EMMC.:D

I now have a full EMMC image, along with individual partition dumps done with DD in Hiren's partition magic Linux, hooray! So in my mind I can do whatever I like, and I should be able to restore from any mess that I make.

But WTF to do now?? Reading through the many posts here, there's talk of flashing partition images from the stock firmware, .mbn and .img etc. Some of them 'seem' easily mapped to partitions:

rpm.mbn > rpm

sbl1.mbn > sbl1

sdi.mbn > dbi

tz.mbn > tz

emmc_appsboot.mbn > aboot??

from this folder within the unpacked firmware:

Directory of C:\Android\update-kindle-14.4.5.5_user_455004320\images

30/05/2014 22:26 358,404 emmc_appsboot.mbn

30/05/2014 22:26 155,880 rpm.mbn

30/05/2014 22:26 277,076 sbl1.mbn

30/05/2014 22:26 18,004 sdi.mbn

30/05/2014 22:26 322,744 tz.mbn

5 File(s) 1,132,108 bytes

But if you unpack the fwupdate.tar, there seem to be duplicates:

Directory of C:\Android\update-kindle-14.4.5.5_user_455004320\images\fwupdate

27/08/2013 03:16 70,944 appsboot.mbn

12/10/2013 22:25 3,428,888 dsp1.mbn

12/10/2013 22:25 34,903,448 dsp2.mbn

27/08/2013 03:16 464 partition.mbn

27/08/2013 02:04 104,360 rpm.mbn

27/08/2013 02:04 115,308 sbl1.mbn

27/08/2013 02:04 368,684 sbl2.mbn

7 File(s) 38,992,096 bytes

And which boot image to dd to which boot partition?:

Directory of C:\Android\update-kindle-14.4.5.5_user_455004320

30/05/2014 22:26 7,766,016 boot.img

1 File(s) 7,766,016 bytes

Directory of C:\Android\update-kindle-14.4.5.5_user_455004320\images\fwupdate

27/08/2013 03:16 5,591,040 boot-oe-msm9615.img

1 File(s) 5,591,040 bytes

I found this reference in the install-recovery.sh, and one of the references below match the boot.img above:

"#!/system/bin/sh

if ! applypatch -c EMMC:/dev/block/platform/msm_sdcc.1/by-name/recovery:9525248:ba9ceca5992d27e1a24d630f54991376082375f0; then

log -t recovery "Installing new recovery image"

applypatch -b /system/etc/recovery-resource.dat EMMC:/dev/block/platform/msm_sdcc.1/by-name/boot:7766016:5cd16d9155f1e148b867dfbbbde5e4ce0faee8c9 EMMC:/dev/block/platform/msm_sdcc.1/by-name/recovery ba9ceca5992d27e1a24d630f54991376082375f0 9525248 5cd16d9155f1e148b867dfbbbde5e4ce0faee8c9:/system/recovery-from-boot.p

else

log -t recovery "Recovery image already installed"

fi"

Linux is not my strong point, Me being a mainly M$ based IT tech, but I'm a quick learner - if only I can stop my eyes from going curly.

Any tips, pointers or even a bit of humour at this point would be greatly appreciated.

Thanks for reading.