KoboRoot.tgz

[bsammon]

I recently acquired my first Kobo device, and I want to customize/hack it.
I see a lot of references to KoboRoot.tgz, but most of the stuff I find assumes a level of knowledge that I don't possess.

Is there a good introductory document about the KoboRoot.tgz system that I should read before I start bombarding this forum with questions?

[DNSB]

Basically, the KoboRoot.tgz file is part of the automated installation system. New Kobo firmware and third party modifications use that file for installations.

For example, when you use the KoboPatcher, the output file from the patcher is a KoboRoot.tgz file which gets copied into the .kobo directory in the root of the exposed partition (what you see using a USB connection) and will be automagically installed when you eject your Kobo.

[bsammon]

I wasn't able to find any detailed documentation/FAQ, but I did find some answers in my wanderings around the forum. Some were relatively definitive, while in some cases all I have is guesses based on reading between the lines.
Here's my questions and the answers I have:

Does KoboRoot.tgz contain an _entire_ root filesystem, or just some files to add/change?
It's just the files that are being added or changed. It's like a patch file.

Do the KoboRoot.tgz files get automatically deleted from the device?
Yes, if the install/upgrade is successful, the file should be automatically deleted. If the file is still there, try rebooting and see if something gets installed or if the file is still there after the reboot. If that doesn't work, advanced troubleshooting is necessary to figure out why it didn't work.

Does the KoboRoot.tgz system only do add-file and modify-file, or can it do delete-file as well?
Not sure. It can (most likely) do replace-file-with-zero-length-file, and that's almost as good as delete-file.

[lumping-sugar66]

KoboRoot.tgz is the file that kobo devices use to detect software updates. If such a file exists, the device will consider it a valid update file and use it. It typically consists of replacing/adding files from the device's filesystem with new ones, or adding new ones, usually new libraries. we can intervene and supply the system with KoboRoot.tgz files of our own and trick the system to using them, hence our mods. The contents of the KoboRoot.tgz will depend on the mod, but if you were to unarchive the package, you'd see a folder structure that will resemble a standard Linux structure if you're familiar with it.

Mod developers (myself included) typically use geek1011's NickelHook tool suite to develop mods and package them with a KoboRoot.tgz. There's also the Kobopatch project, which will let you pick and choose from many customization options and install them with a single KoboRoot.tgz.

Single-purpose, small mods that are built with NickelHook are more general purpose, that's why you can find their KoboRoot.tgz files readily available. My mod, NickelNote, for instance, is hosted on GitHub and the zip file over there contains the KoboRoot.tgz

https://github.com/onatbas/nickelnote/releases

It contains a single compiled binary of my mod which does the "hooking"

/usr/local/Kobo/imageformats/libnickelnote.sh

.

If you're going with the kobopatch route, since it's highly personalized and configured based on what you want, the KoboRoot.tgz file will have to be created by you, using the instructions on the project page. It's straight-forward but requires some tinkering.

[noobyme]

Originally Posted by lumping-sugar66

KoboRoot.tgz is the file that kobo devices use to detect software updates. If such a file exists, the device will consider it a valid update file and use it. It typically consists of replacing/adding files from the device's filesystem with new ones, or adding new ones, usually new libraries. we can intervene and supply the system with KoboRoot.tgz files of our own and trick the system to using them, hence our mods. The contents of the KoboRoot.tgz will depend on the mod, but if you were to unarchive the package, you'd see a folder structure that will resemble a standard Linux structure if you're familiar with it.

Mod developers (myself included) typically use geek1011's NickelHook tool suite to develop mods and package them with a KoboRoot.tgz. There's also the Kobopatch project, which will let you pick and choose from many customization options and install them with a single KoboRoot.tgz.

Single-purpose, small mods that are built with NickelHook are more general purpose, that's why you can find their KoboRoot.tgz files readily available. My mod, NickelNote, for instance, is hosted on GitHub and the zip file over there contains the KoboRoot.tgz

It contains a single compiled binary of my mod which does the "hooking"
.

If you're going with the kobopatch route, since it's highly personalized and configured based on what you want, the KoboRoot.tgz file will have to be created by you, using the instructions on the project page. It's straight-forward but requires some tinkering.

Is the KoboRoot.tgz just a compressed file? can i unzip it and add things then rezip? i dont want to bootloop my ereader so ithought id ask before i attempt it. ijust wanna add kobostuff, nickelmenu and koreader into asingle install as well as removing unncecessary stuff from kobostuff cuz that makes my nia crash alot

[DNSB]

Originally Posted by noobyme

Is the KoboRoot.tgz just a compressed file? can i unzip it and add things then rezip? i dont want to bootloop my ereader so ithought id ask before i attempt it. ijust wanna add kobostuff, nickelmenu and koreader into asingle install as well as removing unncecessary stuff from kobostuff cuz that makes my nia crash alot

You can do whatever you want with adding/removing files from KoboRoot.tgz. However there is no protection against you doing anything that might turn your Nia into an expensive paperweight. I would strongly suggest removing the internal µSD card and creating an image from it to give you a backup for when you brick your Nia.

[noobyme]

Originally Posted by DNSB

You can do whatever you want with adding/removing files from KoboRoot.tgz. However there is no protection against you doing anything that might turn your Nia into an expensive paperweight. I would strongly suggest removing the internal µSD card and creating an image from it to give you a backup for when you brick your Nia.

Hmm yea i have already bricked my nia which is why i ask, luckily i was able to factory reset it, and then i imaged the sd card. sodid the original creators have checks built in? if so what are they called? i dont recall seeing anything that might be a check

[DNSB]

Originally Posted by noobyme

Hmm yea i have already bricked my nia which is why i ask, luckily i was able to factory reset it, and then i imaged the sd card. sodid the original creators have checks built in? if so what are they called? i dont recall seeing anything that might be a check

It's an open system. You are not protected from your actions. You can do damn near anything and it will be applied. If you are feeling very enthused, you can even overwrite the factory restore partition. I did that one time while trying to update the factory restore partition to restore to a firmware version newer than the original factory. I managed to get it to work but was happy that I had a restore image since my first attempts either didn't work or bricked my Glo.

[noobyme]

Originally Posted by DNSB

It's an open system. You are not protected from your actions. You can do damn near anything and it will be applied. If you are feeling very enthused, you can even overwrite the factory restore partition. I did that one time while trying to update the factory restore partition to restore to a firmware version newer than the original factory. I managed to get it to work but was happy that I had a restore image since my first attempts either didn't work or bricked my Glo.

Ihavent yet figured out how to replicate the structire , when viewing the zip contents inzarchiver it shows the root folder being the relative path period, which doesnt show up me when i rezip the contents. im not sure if this is a zarchiver thing or if its actually there. besides ive already been thrpugh the trouble of pryingthe back open, iwant to keep waiting until i can be bothered to reopen it beforeiexperiment.

how did you overwrite the factoryrestore partition? utook the sd card out correct? not using the zip file

[DNSB]

Originally Posted by noobyme

how did you overwrite the factoryrestore partition? utook the sd card out correct? not using the zip file

I took out the µSD card and examined the contents of the restore partition. I then attempted to duplicate that as closely as possible. It took a few efforts but I finally got a working version. As it turned out, I needed to pretty much as much work to update the restore partition every blasted firmware update and/or new device so I finally decided for the few time I actually used the restore functionality, it just wasn't worth the effort. That was back when I had a Kobo Glo before I updated to an Aura HD.

I generated a KoboRoot.tgz to do the restore partition update since that was the easiest way to do the update without extracting the µSD everytime.

[noobyme]

Originally Posted by DNSB

I took out the µSD card and examined the contents of the restore partition. I then attempted to duplicate that as closely as possible. It took a few efforts but I finally got a working version. As it turned out, I needed to pretty much as much work to update the restore partition every blasted firmware update and/or new device so I finally decided for the few time I actually used the restore functionality, it just wasn't worth the effort. That was back when I had a Kobo Glo before I updated to an Aura HD.

I generated a KoboRoot.tgz to do the restore partition update since that was the easiest way to do the update without extracting the µSD everytime.

I see. Thanks for telling me. Ive successfully recreated the dot folder structure ., had to use tar on linux wsl rather than 7zip on windows, "tar -czf /path/A.tgz -C /path/yourdir ." with the dir being the one with the extracted /mnt /bin /sbin etc