About the capabilities of modding a jailbroken Kindle

[Mino101]

I just heard of the new jailbreak method.
I'm not particularly interested in KOReader or tools that completely change the functionality, but I want slight modifications like:
- overwriting the translate API to use Google translate or DeepL
- having the "wikipedia" mini window show custom results like from ChatGPT
All modifications are to be made in the built-in reader.
I want to know if these modifications are possible, even if no one's done it yet, I'll try to do it myself.

Any information would be appreciated.

[thejist92]

Thanks for posting this - was about to post something similar. I have a Scribe. I've been perusing this forum and some of the recent Winterbreak posts, and I still can't really determine where to start if I want to develop something.

In particular, on my Scribe, when I create a new notebook, it's titled YYYY-MM-DD + "title". I'd like to create a button that enters the current date in that format into the text field.

It's just little QoL things to speed up some things here and there.

[BionicGecko]

I asked a similar question here a while back; you can find the thread here. Of particular interest is this answer by HackerDude (who wrote WinterBreak).

In a nutshell, it is very hard to modify the Kindle native UI, as the source code is not available and the binaries are highly protected against reverse-engineering.

[Mino101]

Originally Posted by BionicGecko

In a nutshell, it is very hard to modify the Kindle native UI, as the source code is not available and the binaries are highly protected against reverse-engineering.

Thanks for the info, I'm still willing to tackle the challenge,
so you have put me on the right track.

Originally Posted by HackerDude

Whilst it could be theoretically possible to modify, say, the home screen code, unfortunately, since it now uses WASM it is extremely difficult to reverse engineer.

That's the kind of information I wanted to know. The fact that the UI uses WASM is indeed a hurdle, even though I am sure it's able to be cracked with some work. There is WASM tools that should make the task possible. For simple QoL improvements it should be feasable.

Though I have a question in mind as I'm new to the universe of jailbreaking, if I was able to successfully mod the code, what are steps to apply it to the kindle, just replace the file and reboot ?

Can I also be pointed to which binaries I need to look into ? (Please attach if possible, I didn't jailbreak my kindle yet)

[BionicGecko]

The MobileRead forums are great for end-users but if you're interested in actively developing for the Kindle I would strongly suggest you join the Kindle Modding Community on Discord.

All the devs hang out there and you will get answers to your development-related questions much quicker than here on the forums. There is also definitely some interest in hacking the official GUI amongst some of the other users there.

[Mino101]

Originally Posted by BionicGecko

The MobileRead forums are great for end-users but if you're interested in actively developing for the Kindle I would strongly suggest you join the Kindle Modding Community on Discord.

All the devs hang out there and you will get answers to your development-related questions much quicker than here on the forums. There is also definitely some interest in hacking the official GUI amongst some of the other users there.

Alright thanks

[Mino101]

Sharing my progress:

[cdhigh]

Originally Posted by Mino101

Sharing my progress:

Can you modify this page to become an AI assistant?
Inkwell - Kindle AI Assistant


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[Mino101]

Originally Posted by cdhigh

Can you modify this page to become an AI assistant?
Inkwell - Kindle AI Assistant


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That's what I intend to do. I am planning to redirect the call to a custom server, where I wil call the AI APIs.
Do you think I can renounce the server and call the API directly from within the kindle using Inkwell ? I think to make it possible, we should implement a local server in Inkwell that's always listening, is it possible ?

[cdhigh]

Originally Posted by Mino101

That's what I intend to do. I am planning to redirect the call to a custom server, where I wil call the AI APIs.
Do you think I can renounce the server and call the API directly from within the kindle using Inkwell ? I think to make it possible, we should implement a local server in Inkwell that's always listening, is it possible ?

Given the Kindle's limited CPU and RAM, writing comprehensive Java code directly is recommended over calling Python scripts.
If you can successfully hack the Wikipedia page to customize its GUI (at least with an input textbox and an output textbox and a pop-up keyboard), implementing simple Java functions to connect to an AI server should be relatively straightforward.
The SimpleAiProvider class in my Inkwell project already wrap the APIs of several AI services into a unified interface, making the Java conversion process even easier.
Or writing only an OpenAI API is enough.


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[Mino101]

Originally Posted by cdhigh

Given the Kindle's limited CPU and RAM, writing comprehensive Java code directly is recommended over calling Python scripts.
If you can successfully hack the Wikipedia page to customize its GUI (at least with an input textbox and an output textbox and a pop-up keyboard), implementing simple Java functions to connect to an AI server should be relatively straightforward.
The SimpleAiProvider class in my Inkwell project already wrap the APIs of several AI services into a unified interface, making the Java conversion process even easier.
Or writing only an OpenAI API is enough.


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I want to refrain from embedding the AI code in the patched jars, because the APIs change frequently and it wouldn't be convenient to update the patches in the kindle everytime, that's why I want to redirect the calls to a custom server and do all the work there. It would be much easier to maintain and more customizable.

[Mino101]

I'm having some problems with patching the jars, I created a public static function that returns a constant and included it in the jar, and patched the jar to call when wikipedia mini window is shown, but the window gets stuck in "Searching Wikipedia..." even though I didn't change anything. Maybe the classloader is excluding the custom classes I have written because they aren't in the "com.amazon" package but it doesn't make a lot of sense. It's driving me crazy

[Mino101]

Problem solved:
The problem was that I accidentally set the Java version to 19, while Kindle works with Java 1.8, so it silently ignored the classes I've written

Update:

WIkipedia URL is now configurable via a file

[shamanNS]

@Mino101Could you maybe look into why the edited hardcoded values for margins (that are inside " "/opt/amazon/ebook/lib/ReaderSDK-impl-*.jar" files) aren't being used (even after a OS reboot) by the reader / renderer software since firmware 5.10.x? To figure what and where overrides them.

Some links as a starting point:

https://www.mobileread.com/forums/sh...postcount=1795

https://www.mobileread.com/forums/sh....php?p=2527653

[plug313]

thank you for your enthusiasm in developing stuff like that for the kindle. I think what we need at this point is a true CFW with added features that truly make the jailbreak worth it, like a lot of other devices have. I understand that it's difficult but from my experience with hacked consoles developers can do incredible things!

my mind was blown when I installed KOReader and saw that you can't just browse and read your actual Kindle books on it... the app is awesome don't get me wrong but I thought that would be the most basic feature