Kobo + PPPoE + scrcpy

content/post/kobo-adventures.md

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+---
+title: "Kobo Adventures"
+description: How to get root access on a Kobo without USB
+date: 2026-02-10T22:52:20+01:00
+image: 
+math: 
+license: 
+hidden: false
+comments: true
+draft: true
+---
+
+TL;DR You can use the UART to access uboot, change the boot args, boot and change the password so you can log in and enable ssh/remote access.
+
+I like technology almost as much as I like a bargain.
+For a while now I've been buying used kobos for friends and for personal projects.
+Kobos are very friendly for tinkerers: a side-loading mode (no cloud), a simple mechanism to install apps and customize the system and a vibrant community.
+This means you can easily install Koreader on it.
+After using it on my kindle for years, I just can't use the stock reader. Ok, it's not such a big deal, but I really like the configurability and the extra niceties.
+
+Older kobos are even better, because most of them have an internal SD card instead of an eMMC, so you can easily recover if you mess up the system.
+Sadly, newer devices (and h2o models) no longer have an SD card.
+Supposedly, for waterproofing
+Another recent change is that newer firmwares stopped allowing telnet and ssh access to the device by default.
+
+This post tells the story of how I managed to get remote access and install custom applications on a newer device with a missing USB port.
+
+## What I got
+
+I bought a used Kobo Libra H2O.
+The listing said the battery would not charge well or at all after getting it replaced by an unofficial technician.
+I risked it, hoping it would be a relatively easy port issue, and I would be able to get around it, even if I needed some ugly hack.
+
+My plan was to fix the port, or at least try, and get it to charge some way.
+
+* Fix the port
+* Install Kobo
+
+## Fixing the port
+
+I will skip this section for now.
+
+Long story short: the connector that connects the motherboard to the USB daughterboard was broken.
+
+## Failed attempts
+
+* Hand-wiring a USB connector to contact points in the daughterboard. Either something else was broken or I was missing resistors/components.
+* Downloading files from the browser
+* Logging using UART
+
+What I didn't try: buying and soldering a new connector.
+To be honest, I am not sure I would be able to properly solder it without melting the plastic parts.
+Even then, I wasn't sure the rest of the board was functional, because my attempts to manually wire it had failed.
+
+## U-boot
+
+Connect the UART, reboot the reader and press a key while it boots.
+You will be greeted by u-boot.
+
+U-boot can actually list your mmc contents, you can load files to memory and write them to specific locations.
+If you know how to use that, great, just remove `.kobo/ssh-disabled` from the user partition and create a file named `.kobo/ssh-enabled`.
+I personally don't feel too comfortable raw editing the contents of the file system, and I was afraid of breaking something.
+Luckily, there is an easier way.
+
+
+If you take a look at the environment, you will recognize some of the variables that are used for booting.
+In particular, one of them has the linux boot parameters.
+Use `setenv` to modify it to add this at the end:
+
+```
+single init=/bin/sh
+```
+Now, boot from mmc.
+
+## Changing the root password
+
+Once booted, it is just a matter of changing the password:
+
+```
+passwd root
+```
+There might be some warnings about weak passwords, but it will let you set it anyway.
+The user partition is not mounted, and I got errors while trying to do it manually, so just `reboot`.
+
+
+## Enabling remote access
+
+use `root` and the password you just set to log in the normal system.
+
+```
+# I believe these are the correct paths, but check before running the command
+cd /mnt/onboard/
+rm .kobo/ssh-disabled
+touch .kobo/ssh-enabled
+reboot
+```
+
+## SSH
+
+Connect your Kobo to your wifi, and ssh to it.
+You will be asked to change the password on your first login.