Patch PNG images in Kobo firmware

[pipcat]

I don't have any need to change Kobo images, but poking around I made some simple python scripts to search, extract and patch them. This is really not very useful, but if someone is interested, it's not difficult to do.

For example, you can change the image shown on "About Kobo" with your prefered logo or a customized photo.
It's easy to do because there is only one image (790 x 330 px) for each device model and it's easy to locate.

But depending of wich images you want to change, there could be many variations for diferent devices/resolutions, and you should try-and-hope to know wich ones are used on your device. There are 1.239 images in nickel 3.19.5761, about 2,6 mb.

Readme.txt:

Spoiler:

Tool to extract and patch png images inside Kobo binaries
=========================================================

- python search.py
	- Edit variable KOBO_FW_FOLDER to fill your path to Kobo firmware files.
	- Execute to find streams in Kobo firmware files.
	- With firmware 3.19.5761 we get this:
	0 zlib streams, 58 png streams. libchess.so
	0 zlib streams, 8 png streams. libcrossword.so
	0 zlib streams, 7 png streams. librushhour.so
	52 zlib streams, 0 png streams. libsolitaire.so
	{'.css': 0, '.mng': 0, '.png': 0, '.txt': 52, '.qm': 0}
	2 zlib streams, 20 png streams. libsudoku.so
	{'.css': 0, '.mng': 0, '.png': 2, '.txt': 0, '.qm': 0}
	43 zlib streams, 1239 png streams. nickel
	{'.css': 25, '.mng': 1, '.png': 4, '.txt': 2, '.qm': 11}

- python extract-png.py
	- Edit variable KOBO_FW_FOLDER to fill your path to Kobo firmware files.
	- Execute to extract png images.

- If you want to modify images, some tips:
	- Edit the png images you want to modify with your preferred software.
	- Don't remove image number and hexadecimal position from images filename (it's needed to find them in binaries when patching!)
	- New png images could not be larger than original ones!
	- Normally you can't change a simple image with a high-resolution photo for example because you are limited by filesize.
	- But you can make some changes if you careful and optimize image.
	- After your changes, use a compressor to reduce image filesize. Ex: compresspng.com optimizepng.com tinypng.com etc...

- nickel images:
	- There are 1.239 png embedded in nickel 3.19.5761
	- Some images are repeated with diferent resolutions for diferent devices.
	- You probably must try-and-hope to locate wich images you need to change for your device.
	- I only changed an image shown on my "About Kobo Glo Hd" (nickel-0375-175c6a.png) with a custom logo, 
	because it was very easy to locate (1 ocurrence with Model N437)

- python patch-png.py
	- Edit variable KOBO_FW_FOLDER to fill your path to Kobo firmware files.
	- Edit variables NEW_IMAGES and calls to patch_pngstreams with your selection.
	- If you already patched nickel, you may want to indicate it in call to patch_pngstreams.
	- Execute to patch png images.

- Execute ./publish.sh to create KoboRoot.tgz, and copy to folder .kobo/ in your device.
	- Edit lines starting with cp $DIR_BINARY/ to select wich files to patch.

[frostschutz]

I also had a mod that does this:

https://www.mobileread.com/forums/sho...d.php?t=262837

It's fun but I think your CSS idea is more interesting, though.

( We need a Kobo Mods database too, not just hacks/patches... something like https://ankiweb.net/shared/addons/ )

[pipcat]

Thx frostschutz, your post with nickelicons was nice and with good tips, I didn't saw it. The main difference is that your script run on device and mine on pc. I agree with you, it's fun but not so useful ;-D

A Kobo Mods database (KMD) could be nice ;-)
- With patches we can load all data from Metazoa packs, but this can't be done with Mods and will require "human loading".
- Patches also have a defined structure, that allows to manage them, but I'm not sure how to proceed with Mods.
- Any ideas, suggestions of what to include in KMD ? ...

[Jellby]

Originally Posted by frostschutz

( We need a Kobo Mods database too, not just hacks/patches... something like https://ankiweb.net/shared/addons/ )

Originally Posted by pipcat

A Kobo Mods database (KMD) could be nice ;-)

And perhaps the wiki would be a better place to host it (within MR) than a forum thread. At least that could be a start.

[frostschutz]

Originally Posted by pipcat

The main difference is that your script run on device and mine on pc.

Yes, I like to run things directly on the device whenever possible. Did it for collections (AutoShelf) and firmware patches too (AutoPatch mod, but discontinued due to lack of popularity ), maybe with your database it would be possible to (de)select patches directly on the reader itself without help from PC. But the way patches currently work, you're supposed to edit them (sometimes it's three patches in one, with two variants commented out) and editing probably won't work too well if you have to do it directly on the reader...

On the other hand it's a huge time investment to develop such things (to a decent level) and at some point you just prefer to spend that time ing...

Haven't actually developed anything for Kobo in a while

[surquizu]

Originally Posted by frostschutz

.

Haven't actually developed anything for Kobo in a while

I use the autoself and I still waiting The Remote Page Turning Controller for make my button and install it on the reader.

[pipcat]

Originally Posted by frostschutz

Yes, I like to run things directly on the device whenever possible. Did it for collections (AutoShelf) and firmware patches too (AutoPatch mod, but discontinued due to lack of popularity ), maybe with your database it would be possible to (de)select patches directly on the reader itself without help from PC. But the way patches currently work, you're supposed to edit them (sometimes it's three patches in one, with two variants commented out) and editing probably won't work too well if you have to do it directly on the reader...

On the other hand it's a huge time investment to develop such things (to a decent level) and at some point you just prefer to spend that time ing...

I like how you nicely run things on the device, very interesting. That gives a better understanding of Kobo internals. But I also like to run things outside the device because I feel more comfortable.

If you want current KHD database returns a new format for your needs to patch directly on the reader, I can add. Normally, I prefer to write code than to read, no problem ;-)

I had troubles connecting to my home hidden wi-fi, so I disabled it because all my ebooks are side-loaded and don't need it. And I never tried Kobo browser, I don't know if KHD website with bootstrap/jquery is rendered ok and if login, editing and downloading is possible.

If a Mod were only a collection of patches, it could be already done with KHD website. A user profile is like that, a collection of (de)select patches that can also be edited. Editing patch code from Kobo is probably not too much comfortable, but you can have your profiles updated once from pc and only select them from device.

[boriar]

Originally Posted by frostschutz

Yes, I like to run things directly on the device whenever possible. Did it for collections (AutoShelf) and firmware patches too (AutoPatch mod, but discontinued due to lack of popularity ).
Haven't actually developed anything for Kobo in a while

I really like both!!!
AutoShelf is the only method for me to use nickel . I dislike the standard collections.
And allways update my patch collections for AutoPatch.

[surquizu]

Originally Posted by pipcat

I don't have any need to change Kobo images, but poking around I made some simple python scripts to search, extract and patch them. This is really not very useful, but if someone is interested, it's not difficult to do.

For example, you can change the image shown on "About Kobo" with your prefered logo or a customized photo.
It's easy to do because there is only one image (790 x 330 px) for each device model and it's easy to locate.

But depending of wich images you want to change, there could be many variations for diferent devices/resolutions, and you should try-and-hope to know wich ones are used on your device. There are 1.239 images in nickel 3.19.5761, about 2,6 mb.

Readme.txt:

Spoiler:

Tool to extract and patch png images inside Kobo binaries
=========================================================

- python search.py
	- Edit variable KOBO_FW_FOLDER to fill your path to Kobo firmware files.
	- Execute to find streams in Kobo firmware files.
	- With firmware 3.19.5761 we get this:
	0 zlib streams, 58 png streams. libchess.so
	0 zlib streams, 8 png streams. libcrossword.so
	0 zlib streams, 7 png streams. librushhour.so
	52 zlib streams, 0 png streams. libsolitaire.so
	{'.css': 0, '.mng': 0, '.png': 0, '.txt': 52, '.qm': 0}
	2 zlib streams, 20 png streams. libsudoku.so
	{'.css': 0, '.mng': 0, '.png': 2, '.txt': 0, '.qm': 0}
	43 zlib streams, 1239 png streams. nickel
	{'.css': 25, '.mng': 1, '.png': 4, '.txt': 2, '.qm': 11}

- python extract-png.py
	- Edit variable KOBO_FW_FOLDER to fill your path to Kobo firmware files.
	- Execute to extract png images.

- If you want to modify images, some tips:
	- Edit the png images you want to modify with your preferred software.
	- Don't remove image number and hexadecimal position from images filename (it's needed to find them in binaries when patching!)
	- New png images could not be larger than original ones!
	- Normally you can't change a simple image with a high-resolution photo for example because you are limited by filesize.
	- But you can make some changes if you careful and optimize image.
	- After your changes, use a compressor to reduce image filesize. Ex: compresspng.com optimizepng.com tinypng.com etc...

- nickel images:
	- There are 1.239 png embedded in nickel 3.19.5761
	- Some images are repeated with diferent resolutions for diferent devices.
	- You probably must try-and-hope to locate wich images you need to change for your device.
	- I only changed an image shown on my "About Kobo Glo Hd" (nickel-0375-175c6a.png) with a custom logo, 
	because it was very easy to locate (1 ocurrence with Model N437)

- python patch-png.py
	- Edit variable KOBO_FW_FOLDER to fill your path to Kobo firmware files.
	- Edit variables NEW_IMAGES and calls to patch_pngstreams with your selection.
	- If you already patched nickel, you may want to indicate it in call to patch_pngstreams.
	- Execute to patch png images.

- Execute ./publish.sh to create KoboRoot.tgz, and copy to folder .kobo/ in your device.
	- Edit lines starting with cp $DIR_BINARY/ to select wich files to patch.

It works well , but for use with Windows is necessary to create the folder pngs

[pipcat]

Originally Posted by surquizu

It works well , but for use with Windows is necessary to create the folder pngs

Ok, thx. Yes, you need to create the folder where you want to extract (pngs/ by default) or change variable PNG_EXTRACT_FOLDER with your choice. I updated extract-png.py in https://github.com/pipcat/kobo/tree/...tch-images-png to include width and height in filenames, as tshering suggests on frostschutz post, because it's easier to find images for our device.

[pipcat]

Originally Posted by frostschutz

Yes, I like to run things directly on the device whenever possible. Did it for collections (AutoShelf) and firmware patches too (AutoPatch mod, but discontinued due to lack of popularity ), maybe with your database it would be possible to (de)select patches directly on the reader itself without help from PC. But the way patches currently work, you're supposed to edit them (sometimes it's three patches in one, with two variants commented out) and editing probably won't work too well if you have to do it directly on the reader...

Haven't actually developed anything for Kobo in a while

frostschutz, do you want to continue with AutoPatch, to process patches downloaded from website KHD ? That could be interesting, as you suggested ;-) More info: https://www.mobileread.com/forums/sho...8&postcount=11

[boriar]

Please, say YES!