[7" Kindle Fire HD Q&A, Help & Troubleshooting] bogie6040:
PART 2

Prerequisites:

Ubuntu or other linux distro with gparted utility access

7.2.3 bootloader file from here: SEARCH FOR TOPIC # 2128848 by hashcode (Step 2 item 6)

Now that you have it all soldered up it should look something like this....

View attachment 3544917

Note that I put some tape over the wires on the board and on the SD card adapter, this is for stress relief - you don't want your wires breaking off or worse, a surface mount pad ripped off the board...

Now plug the micro SD card adapter into your USB SD card reader and connect it to your Ubuntu Linux computer, preferably with a USB extension cable.

DO NOT try to power up the board with another power source, ie additional USB cable, etc. The card reader is all you need.

View attachment 3544918

Ubuntu should see the eMMC chip and you should have 13 separate partitions, if you can't see it make sure your linux has mounted it. If you have run the lsusb command and still don't see a new device then disconnect it and double check your soldering / wiring work.

Open up gparted and change to the device representing the eMMC we just soldered to, you need to write down the device name (sdb, sdc, sdd, etc.) take a look at the partition table - mine had 13, I'm assuming that you need at least 1 and 2 for the kindle to do anything and I'm guessing that partition 1 never gets touched by the erroneous procedure ie: flashing files intended for KF2 or others (which is what got you in this situation in the first place)

Perhaps someone more knowledgeable on kindle partitions and their theory of operation will chime in on this note...

In any case you can look here: SEARCH FOR TOPIC # 1919556 by timmytim for what the partition table should look like - that is how mine looked...

Now exit out of gparted.

If all appears ok with the partition table copy the file from the prerequisites list and place it in your home folder on Ubuntu (or the folder your terminal program defaults to) Now open up a terminal window and type in the following:

sudo dd bs=1 if=kfhd7-u-boot-prod-7.2.3.bin of=/dev/sdg2

where sdg at the end, is the device name from gparted earlier.

MAKE SURE YOU GET THIS CORRECT! I can't stress this enough - there is a reason the dd command has been nick named "data destroyer"....

This should take all of 6 seconds and mine did not give any errors.

At this point all there is left to do is try it out reinstalled into the kindle. When I did mine I left the wires and SD card adapter attached EXCEPT I removed the brown wire (DAT3) from TP805 and one end of the jumper wire from capacitor C803 Insulate the ends of these wires with tape and reinstall the board temporarily back into the kindle.

LEAVE THE SD CARD ADAPTER UNPLUGGED from your reader!! ALSO OBSERVE ESD PRECAUTIONS while testing / loading software!!

This saves having to unsolder and resolder everything a bunch of times if something didn't work on the software side. If you do it this way make sure you tape the wires down to the board and when you reinstall the board temporarily, the wires should come out on the left bottom edge (there is somewhat of a pocket there between the board and the rest of the kindle) make sure you only put a screw or two in on the right side next to all the flex cable attachments - the wires DO make the board sit up a little bit so don't put in any more than those one or two right side screws (they are silkscreened H1 & H5) OR YOU MAY CRACK YOUR BOARD!

Once you are sure you have an accessible kindle you can go ahead and de-solder and remove all of the wires from the board then properly reassemble the kindle.

Mine at this point booted up as a "normal" kindle again... YMMV You may have to do some softbrick recovery as mentioned elsewhere and earlier in this topic. At this point I followed from start to finish the guide from hashcode (the link in the prerequisites) and got the cyanogen mod CM12.1 up and running. I however didn't care for this ROM as the boot time was long and I could not get the google play games part of the play store to allow me to access and link my boom beach account. So I loaded the Slim LP ROM Here: SEARCH FOR TOPIC # t3223314 by Ph0enix_216 since this ROM boots up faster and has more of a standard android phone feel. I then loaded the gapps as suggested in this thread: SEARCH FOR TOPIC # t3241031 by SuperMechaCow using the aroma graphical installer. Everything seems to work good with this setup and I now have a kindle that is more use-able then it was originally.