530 votesBruce Nelson commented
When I had to replace my flip phone, I bought an android to which I could add an SD card. Bought (scrimped) a 64 GB card so I could read the Logos/Vyrso/ Noet resources I have. Olive Tree books go on the SD card. I need the Logos format books on the SD card, not the internal memory. There is an option to move to SD card, but it is "greyed out", unlike Olive Tree and some other apps I have.