For KOReader you can remap all buttons except for home button (maybe back too, I don't remember). You just need the keycodes posted by Renate in
https://www.mobileread.com/forums/sh...13&postcount=6 and a custom keymap following the instructions in
https://github.com/koreader/koreader...customize-keys
The numbers of the left are keycodes. The strings on the right are "known" actions. You can see defaults in
https://github.com/koreader/koreader.../event_map.lua.