

Kobo runs a light linux software called NickelOS on an esp32 board. No android at all. No ability to instal apks. Its not even AOSP.
One can install a custom OS over top called KOreader which expands its usability and offers tons of community led plugins.


I love my kobo precisely because there’s a huge community behind KOreader. Lots of YouTube tutorials, lots of flexibility. My kobo kept dying at like 50% battery and I just assumed it was a bad battery. Turns out NickelOS was trying to cache a book infinitely in the background so the battery calibration was wildly off because it never properly achieved a sleep state when powered down.
I left it sitting for a year and a half. Charged it for a full day to balance the cells, copy pasted the files needed for KOreader, changed a config file so that NickelOS would not cache items in hidden folders, and then threw all my epubs onto a hidden folder called “. books” and boom.
New life in my kobo. I use it daily now. Battery is accurate to 20% (then it sorta doesnt turn back on but whatever). Fair warning though because KOreader is so expansive that its a rabbit hole. UI takes getting used to but the customizability is huge and it runs more efficiently without bloat and you can even use LocalSend to wirelessly push epubs from any device that can run LocalSend to the Kobo so you never have to plug it in again.
I sync book progress from my Xteink X4 pro to my Kobo Clara HD using KOSync and have my own little KOSync instance running on my homelab (but you can just use the public instances if you want).