I just wanna load some epubs on my e-Reader but it's saying it can't read their "Dot Codes" or something

I like to create things.
Perhaps most known for romhacks: Game Boy colorizations, Samus Goes to the Fridge, etc.
I also do OC art from time to time.
I just wanna load some epubs on my e-Reader but it's saying it can't read their "Dot Codes" or something