[dongqiyer]

I've downgraded my KPW2(Japan version) from 5.7.4 to 5.4.3.2, and JB. The KUAL and etc. worked very well.
When it was reseted, the Chinese language option disapeared. If I can let the Chinese Language Option come back.
Many thanks!

Originally Posted by knc1

These directions are written for the experienced (grayscale) Kindle user.

The 6th, 7th, and 8th generation devices listed in the title, running any known firmware version.
Step #1 below describes how to learn what nickname your device has here based on its serial number.

PW-2 users running firmware 5.4.4.2 or older, go directly to:
https://www.mobileread.com/forums/sho...d.php?t=186645

For prior (grayscale) Kindle models, see:
https://www.mobileread.com/forums/sho...d.php?t=275881

Credits:

Spoiler:

• NiLuJe - for discovering the initial factory update could be recovered. PW-2
• knc1 - for posting the 'HowTo' and recovering the KT-2 and PW-3 initial updates.
• Forum members - several members who recovered and provided initial update images for the KV.
• knc1 - recognition that the factory initial update could be re-installed on any (matching) customer model.
• Branch Delay - the original software jb for version 5.6.5 and the generic jb for initial factory images.
• Branch Delay, NiLuJe, Geekmaster - initial testing of the method.
• Geekmaster - archivist of the off-site Kindle recovery resources.
• knc1, Geekmaster, NiLuJe, kindlefere - server resources.
• NiLuJe, Ryccardo, eschwartz - recognizing and testing of the source of the hung Kindles problem.
• Forum member - who recovered the image required to create Oasis support.
• eeeee - who recovered the image required to create updated, PW-3 and PW-3W support.
• ktwombley - who recovered the image required to create KT3 support.
• eschwartz - now the maintainer of Branch Delay's factory image jail break.
• eschwartz, NiLuJe, others - New menu launcher for Oasis (KOA) and other models.
• From kindlefere (here a machine translation) -
• The first public announcement was made by Hackaday, see:
  https://hackaday.com/2016/07/09/a-ja...-every-kindle/
  Which can take credit for many of this thread's views.

A long list of a lot of work done over a period of more than a year. Work that is continuing.
This downgrade attack did not happen over-night nor was it the work of any one person.

Release Policy:

Spoiler:

It is our policy to use a 'single point of maintenance' model for our released items, with two exceptions:.

• NiLuJe's snapshots, use: (filter prefix: tools, show threads).
• Kindlefere.com is providing the distribution links for China.

This means that the user of these directions must click away from this post of directions in order to get the current release of each part.
That is a price one must pay (clicks) to minimize the chance that someone will stumble onto a stale (bit rotted) package of some part.

Step-by-Step:
Consider the following bullet list a "Step #0" that can be done in any order.

• You Kindle must be registered with Amazon to access the required menus.
  If not yet registered, do that now.
• Remove any device passcode or parental control passcode you may have set.
• If you have an ad supported (Special Offers) model consider unsubscribing it at your Kindle account.
  If you do unsubscribe from special offers, be sure to give your Kindle enough time on-line for Amazon's servers to update its local status files.
• Is your Kindle fully charged?
  Get started with that now, put it on a wall charger to be certain.
• Only do one step at a time.
  They are intended and designed to be done one at a time.
  At the completion of a step, if the file you previously put at the top level of visible USB storage is still there, remove it.

1. Positively identify the nickname of your Kindle model from the serial number.
   Of the first six characters, older Kindles: xxxx xx, newer Kindles: xx xxxx in this table:
   https://wiki.mobileread.com/wiki/Kindle_Serial_Numbers
   The factory images **are not** model locked, your care taken with this step is your Kindle's only protection! If not found in the table, STOP HERE and tell us.
2. Prepare your Kindle for running an earlier version of the firmware.
   The Kindles have two user storage areas, the one seen over the USB cable and a hidden one.
   The process that wipes the hidden one will also wipe what can be seen over the USB cable.
   
   Spoiler:

   • Make backup copies of the contents of /documents
     You are about to wipe them all out, if you have them pushed to your Kindle's cloud, you should be covered.
     You should not need copies of the contents of /system - the 'system' should re-build them for you.
   • Do not copy the contents of /documents back to the Kindle until after you have returned to the same firmware version that you copied them from.
     The indexer might go crazy if you try anything else than 'back to same place, with same version running'.
   • You are about to loose all of your collections and annotations, kiss them goodbye now.
     You can't reach that hidden directory they are stored in and it is this database that causes most of the problems, so it MUST go.
   • Home -> Menu -> Settings -> Menu -> Reset
     Or whatever the path is on your current firmware version.
     This is the infamous "Reset (to factory defaults)" menu choice, but in this case it is a requirement, a [b]'must use'[b] entry.
3. Download your model's initial factory firmware image using your computer.
   The off-site, index of Amazon Condoned image files can be found here:
   http://pastebin.com/Wdw4L7yT
   Those links **are not** clickable by design, you have to choose one and manually copy-paste it into your browser.
4. Transfer the selected initial factory image from your computer to your Kindle.
   Do not panic if this step is not immediate, put it on a wall charger and wait, some reports claim it can take over an hour for the downgrade to complete. Less than 10 minutes is more typical.
   
   Spoiler:

   1. Connect Kindle to PC with the USB cable.
   2. Place the downloaded update_*.bin file in the topmost, visible level of USB storage (alongside of /documents).
   3. Eject and/or Safely Remove (term depends on OS) the Kindle, USB storage.
   4. Remove the USB cable.
   5. Home -> Menu -> Settings -> Menu -> Update Your Kindle
   6. Confirm
   7. Wait
   
   ** The PW-2 is a special case at this point in the directions **
   1. Use the prior 'universal jailbreak' from this post:
      https://www.mobileread.com/forums/sho...d.php?t=186645
      
   2. Skip the next two steps, you are ready to upgrade if desired.
5. Download and install the current version of Branch Delay's factory firmware jail break.
   The current version is attached to its release post, see:
   https://www.mobileread.com/forums/sho...d.php?t=275887
   
   Spoiler:

   1. Connect Kindle to PC with the USB cable.
   2. Place the downloaded file (an archive - as is) in the topmost, visible level of USB storage (alongside of /documents).
   3. Eject and/or Safely Remove (term depends on OS) the Kindle, USB storage.
   4. Remove the USB cable.
   5. Home
   6. Search bar, enter:
      

      ;installHtml

      Press 'return'
      Yes, the semi-colon is part of the search bar command string.
6. Download and install the current 'hotfix'
   The current version is attached to its release post, see:
   https://www.mobileread.com/forums/sho...postcount=1597
   
   Spoiler:

   1. Unarchive the release archive package.
   2. Connect Kindle to PC with the USB cable.
   3. Place the Update_jailbreak_hotfix_*_install.bin in the topmost, visible level of USB storage (alongside of /documents).
   4. Eject and/or Safely Remove (term depends on OS) the Kindle, USB storage.
   5. Remove the USB cable.
   6. Home -> Menu -> Settings -> Menu -> Update Your Kindle
   7. Confirm
   8. Wait
7. You can now update your Kindle to a newer firmware version, the jailbreak will survive.
   You can get any firmware version for your device from the Amazon download server.
   
   Spoiler:

   1. Go to the Amazon firmware download page for your model.
   2. Copy the full URL of the current firmware release and paste into an editor.
   3. Manually edit the version number to the desired version.
      You can find the version numbers that where released for your model Kindle from the list of source code packages released for your model, see:
      http://www.amazon.com/gp/help/custom...deId=200203720
      The firmware sources and the firmware binaries use the same numeric strings.
   4. Add the blocker directory (folder) name to the top level of visible USB storage if you don't want your Kindle updated over the air.
      The blocker directory is named: update.bin.tmp.partial

Usage:
With all of the above done, how to make use of it.

Spoiler:

1. Any of our after-market add-ins, with an update_*.bin format filename requires the use of the Mobileread Package Installer (MrPI).
   • See KUAL and KUAL extensions section of:
     https://www.mobileread.com/forums/sho...d.php?t=225030
   • This is an "un-archive to top level of visible USB storage" package.
     Be sure that the un-archive tool you use has options set to create directories.
   • KOA and KT3 owners:
     You must run the installer with your new, search bar command: ;log mrpi
     Other models covered in this thread may do the same or may run it from KUAL.
2. Nearly all of our after-market add-ins require an application launcher.
   • See KUAL and KUAL extensions section of:
     https://www.mobileread.com/forums/sho...d.php?t=225030
   • Beginning with version 2.6.40 of the release, the archive contains three (3) different builds of KUAL.
     The 'keyboard' version, the '(old) touchscreen' version, and the new 'KOA, KT3' version.
   • This is not a substitute for reading the README.txt file included in the archive bundle, but ...
     • KOA and KT3 owners:
       You must use the update_*.bin format package of KUAL and you must use the MrPi installer to install it.
     • Other devices:
       The archive still contains the previous 'document' style of KUAL, used by just placing the (correct) KUAL document into the /documents folder of USB storage.
       Note: The new (update_*.bin format KUAL) will run on all touchscreen devices running firmware 5.1.2 or newer.
   • "Nearly all applications require an application launcher" - I was expecting someone to ask . . . .
     KUAL is one of the applications that does not required an application launcher.
     It has a mime type associated with it that tells the system how to run it, when it is selected.