Kobo readers run Linux. I used kobo mini's as moving map display in my glider. The entire thing cost me about 60 euros from eBay. The root system is even an SD

Kobo readers run Linux. I used kobo mini's as moving map display in my glider. The entire thing cost me about 60 euros from eBay. The root system is even an SD card, so you can just swap cards to restore the stock firmware.