Just wanted to give you some quick update:
bought the app for the sake of testing,
pulled it from an emulator,
as I suspected it had "preferExternal", switched to "internalOnly",
tried to install and got [INSTALL_PARSE_FAILED_NO_CERTIFICATES],
using SDK signed with my own cert,
installed.
BUT, when trying to run it recognized a wrong certificate and refused to run saying to download from Amazon again, which uninstalled my copy first and the failed to install.
As I promised I can force it to be installed, but running is completely different matter.
I don't know if I ever will be able to get around this problem which starts with eDGes not having devmapper to handle encryption-decryption.
The same applies to Everlands
https://www.mobileread.com/forums/sho...d.php?t=146535