I just want to report I can use the Hardkernel ODROID-C2 without any eyestrain. This might be useful for anyone who still searches for a usable Kodi device for their TV. I haven't had luck with the Raspberry Pi (same GPU on all models), and I read other devices like Amazon's box can be troublesome, too.
The C2 might also be a good choice to access PCs (that would otherwise cause eye strain) over network via VNC.
Usable operating systems (no eye strain over time):
- Hardkernel's Ubuntu 16.04 v2.3 http://odroid.com/dokuwiki/doku.php?id=en:c2_release_linux_ubuntu
- Hardkernel's Android 5.1.1 v2.8 (I didn't try 6+ yet) + Kodi 17.3
Not as usable (immediate eye strain):
- Arch Linux (uses different Xorg video drivers)
Android + Kodi
On Android, you can just install Kodi like any other app ("from unknown sources") and make the OS boot into Kodi with Hardkernel's pre-installed ODROID Utility app.
https://kodi.tv/download (Use ARMV7A 32BIT)
Fix backspace/delete keys in Ubuntu
If your backspace or delete keys don't work in certain applications like FileZilla, do this:
System - Preferences - Personal - Language Support - Keyboard input method system:
Change from "IBus" to "none" and reboot.
Compile TigerVNC for Ubuntu
TigerVNC is superior to the Ubuntu repository VNC clients, so I compiled it from source.
apt install cmake zlib1g-dev libjpeg-turbo8-dev fltk1.3-dev libxrender-dev
Download the source code at https://github.com/TigerVNC/tigervnc/releases, extract, go into extracted folder and type:
cmake -G "Unix Makefiles"
The compiled binary is in the directory vncviewer/vncviewer.
Deactivate the blue LED
The device has a blue LED that annoyingly pulsates all the time. It can be deactivated in Android with the included ODROID Utility app.
On Linux, you must paste this line into /etc/tmpfiles.d/leds.conf:
w /sys/class/leds/blue:heartbeat/trigger - - - - none
This works on Ubuntu, Arch, and LibreElec. Probably any OS.