I believe Boyue set it up like that in order to have apps already be able to support the page turn buttons when their respective "Page turn using volume keys" features are enabled. Page Left is Volume Down, and Page Right is Volume Up.
This works for me in most reading apps I use (list excludes those that use a continuous format):
- Kindle
- Kobo (haven't purchased anything there yet, but I had tested using samples)
- Tachiyomi
- Comixology (haven't purchased anything there yet, but it should theoretically work)
- Moon+ Reader Pro
- FBReader
- KOReader
- Likebook built-in reader (obviously)
However, in
OverDrive Media Console, the keys end up getting inverted (so Page Left goes to the next page, and Page Right goes to the previous page), and in Libby by OverDrive, it doesn't support page turns using volume keys at all, but as I confirmed on my tablet
(because Likebook uses a non-compliant USB-C implementation that does not support OTG at all), I can still turn pages using the Page Up and Page Down keys on an external keyboard, and I can do the same using the web version of the Libby reader component
(the one launched from the web interface of the library's OD instance (library_name.overdrive.com) and from the library's own mobile app (if they have it; I'm a member of a library that has one)) on my PC.
I had been considering getting my Mimas apart in order to fix an issue with interference being spit out of the earphone jack, and also to see if I could hack the display controller
(part of the reason why I got the Mimas was because it was cheaper than the official E-ink dev kit, plus I could run XSDL early on to develop and then move on to writing directly to the display controller, but it got me further into the world of comics and I enjoy that), but also in order to find a way to hack in USB hosting and to get the RK3368 in the Mimas into "mask ROM" mode (that would then lead to work to get custom ROMs running on it), but never got around to doing so as I'm rather busy.