Comment by skydhash

I gifted my sister my kindle this morning (it was unused for years) after loaded it with azw3 files converted from epub using calibre. The other options is to send epub via email. But I told her to never put it out of airplane mode and get it on WiFi because amazon has deleted my "documents" (that's what they called sideloaded books) before.

I own two kobos, a libra for fiction and an ellipsa for tech books and textbooks. Both have koreader on.