Edit jars on 5.6.1.0.5 (margins, font sizes) -- and non-jb fonthack

[odamizu]

Kindle Voyage Software Update 5.6.2.1 just showed up at:

http://www.amazon.com/gp/help/custom...deId=201630670

I'm guessing, hoping the FONT-RAMP hack still works, but can some kind soul confirm this or teach me how to crack open the update (with a Mac) so I can check for myself?

Merci, danke, thank you.

P.S. I found KindleTool, but I am in way over my head. I used the "extract" command, which gave me a folder containing rootfs.img.gz, rootfs.img.gz.sig, update-payload.dat, update-payload.dat.sig and a folder named imx60_wario containing uImage and uImage.sig. Now I am totally lost

[knc1]

Originally Posted by odamizu

Kindle Voyage Software Update 5.6.2.1 just showed up at:

http://www.amazon.com/gp/help/custom...deId=201630670

I'm guessing, hoping the FONT-RAMP hack still works, but can some kind soul confirm this or teach me how to crack open the update (with a Mac) so I can check for myself?

Merci, danke, thank you.

P.S. I found KindleTool, but I am in way over my head. I used the "extract" command, which gave me a folder containing rootfs.img.gz, rootfs.img.gz.sig, update-payload.dat, update-payload.dat.sig and a folder named imx60_wario containing uImage and uImage.sig. Now I am totally lost

Nope, your totally on the correct path.
un-gzip the rootfs.img.gz giving a rootfs.img
- - - -
The following is how you do it on a Linux install, for a Mac OSx, you may need to run Linux in a VM (or however Apple people do things).
- - - -
The rootfs.img is just that, a binary image of the filesystem backing store. Treat it as such.
Use a 'loop mount' to turn the file into a device and mount it into your directory tree. Just don't write to it.

You will probably find other files in that (just mounted) Amazon part of your directory tree that are also filesystem backing store images that have to be loop mounted.
A file type identification utility (such as: file) will be a big help in finding them.

Then all you need to do (famous understatement, (tm) ) is start searching the contents of the *.jar files with an appropriate reverse engineering tool(s) for 'FONT_RAMP' and the code that uses it.

[odamizu]

Thanks knc1! But I am still lost and fumbling in the dark because I really don't know what I'm doing

When I try to open rootfs.img, I get "mount failed - no mountable file systems"

This may require more tech know-how than I have, but all I'm wanting is to find ReaderSDK-impl.jar and look inside to confirm that it still includes FONT_RAMP:

Spoiler:

public float[] Sy() {
    J b;
    float[] a = b.YTD("/mnt/us/FONT_RAMP");
    if (a != null && a.length > 0) {
        return a;
    }
    return (float[])ResourceBundle.getBundle("com.amazon.ebook.booklet.reader.resources.ReaderResources").getObject("font.size.mapping");
}

If there is an easy way to do this, suggestions greatly appreciated!

[NiLuJe]

@odamizu: Ha, OS X. You're (mostly) screwed.

Mounting ext* is a bitch there (lack of drivers). So, err, forget about it?
Or do it in a Linux VM, which will probably end up being less ugly than finding a darwin or fuse driver that handles ext3 properly, and then that also handles loop mounts (or whatever the OS X equivalent of that is).

[knc1]

Originally Posted by odamizu

- - - -
If this can be easily done, suggestions greatly appreciated!

Duh, what I posted **is** the "easy way".

The only way easier is to wait for someone (the hack's author?) to verify that FONT_RAMP is still present and working in that newer version firmware.

- - - -

PS:
That bit of Java source code you posted -
That is the output of a Java byte-code, decompiler, Amazon doesn't ship the actual source code.

[eschwartz]

[eschwartz@arch ~/Downloads]$ wget http://s3.amazonaws.com/G7G_FirmwareUpdates_WebDownloads/update_kindle_voyage_5.6.2.1.bin
[eschwartz@arch ~/Downloads]$ kindletool extract update_kindle_voyage_5.6.2.1.bin kv_update_5.6.2.1
[eschwartz@arch ~/Downloads]$ cd kv_update_5.6.2.1
[eschwartz@arch ~/Downloads/kv_update_5.6.2.1]$ gunzip rootfs.img.gz
[eschwartz@arch ~/Downloads/kv_update_5.6.2.1]$ mkdir rootfs
[eschwartz@arch ~/Downloads/kv_update_5.6.2.1]$ sudo mount rootfs.img rootfs
[eschwartz@arch ~/Downloads/kv_update_5.6.2.1]$ cp rootfs/opt/amazon/ebook/lib/ReaderSDK-impl.jar ./
[eschwartz@arch ~/Downloads/kv_update_5.6.2.1]$ sudo umount ./rootfs.img
[eschwartz@arch ~/Downloads/kv_update_5.6.2.1]$ unzip ReaderSDK-impl.jar
[eschwartz@arch ~/Downloads/kv_update_5.6.2.1]$ grep -R "/mnt/us/FONT_RAMP" com/amazon/ebook/booklet/reader/
Binary file com/amazon/ebook/booklet/reader/impl/J.class matches

Yay.

Edit: Yes, to be clear -- this is a step-by-step of me downloading the update, extracting it, and searching inside the right java package for the name of the hacks's file. Since a text string cannot be byte-compiled.
Finding it (I did) demonstrates that the hack should still work.

[NiLuJe]

Requisite xkcd comic to go along with that one: https://xkcd.com/272/

:}

[eschwartz]

Also I realized in the process I needed to bump the pkgrel for kindletool because of a nettle update. I should probably be more careful about that seeing as I maintain the package.

[eschwartz]

Originally Posted by NiLuJe

Requisite xkcd comic to go along with that one: https://xkcd.com/272/

:}

[NiLuJe]

@eschwartz: Does this mean gnutls finally handles nettle-3 without breaking everything under the sun?

I think that new gnutls version (3.4.x) is still masked over here in Gentoo-land because, that, in turn, breaks a lot of gnutls-using apps...

Yay....

----

In any case, good, that means building KindleTool on x86_64 will stop spewing a shit-ton of warnings .

(nettle 3 has saner type handling on x86_64, and I switched to the sane API from the get go; while nothing breaks when building against 2.7, it hurts my sensibilities to see those warnings ^^)

[eschwartz]

Arch Linux has moved nettle-3.1 and gnutls-3.4.0 from testing to core. pacman reports the build date was April 9, which would be when it entered testing. pacman logs say I upgraded (from core) on April 19, and I upgrade ~daily.

Looks like they weren't sure either, but apparently it passed scrutiny. Nothing has broken.

[NiLuJe]

Cool .

Although it appears to still be breaking some stuff on Gentoo: https://bugs.gentoo.org/show_bug.cgi?id=546124

Anyways, soon(TM)! .

[tono1020]

Originally Posted by odamizu

Kindle Voyage Software Update 5.6.2.1 just showed up at:

http://www.amazon.com/gp/help/custom...deId=201630670

I'm guessing, hoping the FONT-RAMP hack still works, but can some kind soul confirm this or teach me how to crack open the update (with a Mac) so I can check for myself?

Merci, danke, thank you.

P.S. I found KindleTool, but I am in way over my head. I used the "extract" command, which gave me a folder containing rootfs.img.gz, rootfs.img.gz.sig, update-payload.dat, update-payload.dat.sig and a folder named imx60_wario containing uImage and uImage.sig. Now I am totally lost

I just updated my KV firmware to 5.6.2.1 and FONT_RAMP hack still works!

[knc1]

Originally Posted by tono1020

I just updated my KV firmware to 5.6.2.1 and FONT_RAMP hack still works!

Was the device jailbroken?
Did the jailbreak survive?

Did you have the Backdoor lock installed and locked?
Did it prevent the automatic update, so that you had to manually allow the update?

[odamizu]

@knc1: Ack! Thank you for trying to teach me. Clearly this is beyond my know-how-skill-set

@eschwartz: I am like a small child listening to the grown-ups speak. I think your code means FONT_RAMP is still present and working in 5.6.2.1? If so, thank you for checking!

@tono1020: Yay! Thank you!!