Upgrading kernel kobo touch

[debiatan]

Hi guys,

I'd like to connect a small keyboard to my kobo touch and use it to take notes without having to carry a laptop. I think the touch can operate in USB on-the-go or host mode and allow me to do that. I have recompiled the kernel with hid support and the usbhid module, but so far I have been unable to replace the kernel in the device.

According to this outdated README, I should just place the kernel zImage under .kobo/upgrade/ in the public flash partition and the kernel should be automatically replaced upon unmounting and unplugging the kobo, but that does not work for me. Has any of you replaced the kernel of a kobo touch or know the correct procedure?

I am running 1.9.17 and I have already made a backup of the internal SD card.

Thanks!

[KevinShort]

I installed a new kernel once, and I believe I followed those instructions you linked on where
to put the zImage. However, I can't remember now if it was on the Touch or the Wifi.

So absolutely nothing happens when you put zImage in .kobo/upgrade?

[debiatan]

Yeah, that's it. After unplugging the Kobo it comes back to the main menu screen. It does not reboot and it does not remove the zImage file from the upgrade directory. I've tried rebooting and looking at the /proc/config.gz to see if the new kernel made it's way in somehow but it stays the same.

The original instructions are given for an older kernel, so it's possible they no longer apply for moderately recent firmware revisions. I'll head to GitHub and ask directly the Kobo developers.

Thanks for your reply!

Edit: Link to the bug report

[debiatan]

I was finally able to replace the running kernel by remounting in read-only mode the root partition of the Kobo and then overwritting it with the uImage (not the zImage):

dd if=uImage of=/dev/mmcblk0 bs=512 seek=2048

I probably got something wrong in my kernel .config since it starts (the blue-green LED pattern blinks two or three times) but fails to complete the boot-up process. In the end it may not matter, since I was finally able to compile the hid.ko module (prerequisite for usbhid.ko), which I thought could not be built as a module and had to be included in the kernel.

I'll open a new thread once the keyboard is working.

[KevinShort]

Cool, I'll look forward to seeing your results.

[KoboTouchUser]

Hello,

For kernel to update, you have to create the .kobo/upgrade directory, and put the kernel inside AND you have to create a .kobo/KoboRoot.tgz, even if it is empty ! From the source /etc/rcS :

if [ -e /mnt/onboard/.kobo/KoboRoot.tgz ]; then

(...)
if [ -e /mnt/onboard/.kobo/upgrade ]; then

/etc/init.d/upgrade-wifi.sh
(..)

fi

(...)
fi