Bookmate has previously introduced a method to downgrade Kindle to a lower version firmware in the article ” Kindle Firmware Downgrade Tutorial: Supporting Some Jailbroken Kindle Devices “, but it is only applicable to some jailbroken Kindle devices, and some require Additional installation of the first aid kit plug-in, some need to use special firmware to downgrade, and for newer Kindle devices such as Kindle Oasis 3 and Kindle Paperwhite 5, if neither the first aid kit plug-in nor the applicable special firmware can be downgraded, it cannot be downgraded.
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The little friend xwcoco provided a good news in the message area of the book companion. Netizen katadelos of the MobileRead forum found a new downgrade method [1] , as long as your Kindle has been successfully jailbroken, by simply modifying a file in the Kindle system , you can directly use the lower version of the official firmware to downgrade, no need to install additional plug-ins, and no need to use special firmware.
1. The principle of downgrade
There is a file named /etc/version.txt in the Kindle system, which contains ” system software version “. The firmware upgrade program of the Kindle device will compare the version of the firmware to be updated with this version. If the version is greater than or equal to this version, the update is allowed, otherwise it is rejected. Therefore, we can deceive the firmware upgrade program and downgrade the firmware by replacing the “system software version” in the text file with a “system software version” that is smaller than the current firmware version.
So how do you get a “system software version” that is smaller than the current firmware version of your Kindle device? Amazon provides a source code zip file for each publicly released Kindle firmware. The zip file name contains a string of numbers in addition to the firmware version number that matches the “system software version” number in the text file. There is a one-to-one correspondence, but there are differences in form. We can convert it into the “system software version” required by the Kindle upgrade program through simple rules.
Log in to the Kindle system via SSH and open the file /etc/version.txt to see something similar to the following:
System Software Version: 059-juno_1402_moonshine_rex-380714 Tue Feb 1 02:50:02 UTC 2022 com.lab126.eink.moonshine.os
Find the string of characters after the first line ” System Software Version ” (that is, the “system software version” mentioned above) divided into three parts by a horizontal bar, and take out the first part of the number and the last part of the number, such as the above 059 and 380714 in this example are reassembled into a set of numbers 3807140059 according to such a rule 380714 + 0 + 059.
Then go to the Amazon Kindle device firmware source code page , use the page search function of the web browser to search for the combined value, and you can find the source code compressed package file corresponding to the current firmware of the Kindle device. The firmware version number in the compressed package is also It is consistent with the current firmware version number of Kindle, such as Kindle_src_5.14.2_3807140059.tar.gz in this example.
According to this rule, we can do the opposite, first determine the firmware version to be downgraded, then find the source code compression package corresponding to the firmware of this version, and recombine the required firmware upgrade program through the numbers in the file name. “System Software Version”.
Suppose, if you want to downgrade the jailbroken Kindle Paperwhie 4 whose current version number is 5.14.3.0.1 to version 5.13.3 firmware, you can first find the file name of the corresponding source code compressed file Kindle_src_5.13.3_3676000033.tar.gz , Take out the string of numbers 3676000033 inside, split it into 033 and 367600 , and replace the first and last numbers of the string of characters after “System Software Version” in /etc/version.txt. The replaced content is as follows shown:
System Software Version: 033-juno_1402_moonshine_rex-367600 Tue Feb 1 02:50:02 UTC 2022 com.lab126.eink.moonshine.os
Finally, you can download the official firmware of version 5.13.3 and downgrade it according to the conventional manual upgrade of the official firmware.
2. Downgrade steps
In order to simplify the operation, Bookmate has written the operations involving modifying Kindle system files into an automated shell script, eliminating the tedious steps of manually logging in to the Kindle system and modifying related files. You can downgrade firmware quickly and easily by following these steps:
- Use the options menu below to select your Kindle device model and identify the firmware version to downgrade from the list that appears;
- Download the shell script file ” RUNME.sh ” and the ” official firmware ” file corresponding to the firmware version to the local;
- Connect the Kindle device to the computer with a USB cable, and copy ” RUNME.sh ” to the root directory of the Kindle;
- Eject the disk, enter
;log runmein the Kindle search box and press Enter to automatically modify the “system software version”; - Connect the Kindle device to the computer with the USB cable again, and copy the ” official firmware file ” to the root directory of the Kindle.
- Eject the disk, enter the Kindle interface, and click the menu [Settings → Device Options → Restart] or [Settings → Device Options → Advanced Options → Restart] to restart the Kindle (or long press the Kindle button to restart), and complete the automatic downgrade.
* Tip: The script will back up the original /etc/version.txt file to your Kindle root directory, delete it if you don’t need it.
The currently verified Kindle device models that have been successfully downgraded through the methods provided in this article are Kindle Paperwhite 5 (including the Signature version), Kindle Paperwhite 4, Kindle Paperwhite 3, Kindle Oasis 3, and Kindle Oasis 2. If your Kindle device is also successfully downgraded by the method provided in this article, please leave a message for feedback.
3. Frequently Asked Questions
If you encounter the problem shown below during the downgrade process, you can try the solutions given.
1. What should I do if I get a white screen after downgrading?
If in the state of white screen, connect the Kindle to the computer through the USB data cable, the disk will appear and back up important files, you can create an empty file named DO_FACTORY_RESTORE (without extension) in the root directory of the Kindle, press the Kindle button 40 After restarting in seconds, the Kindle will automatically restore the factory settings, which can usually solve the problem of the white screen.
2. How to disable automatic update?
To disable automatic updates, please refer to the article ” How to Disable Kindle Automatic Updates (Four Steps to Prevent Firmware Upgrades) “.
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