@raven-worx : I've got an answer from BogDan Vatra, in fact Ministro does not support Qt 5.7.x
This is why nothing works when generating APK with Ministro.

Qt5.7.x support will be added some time later. This is a bad news for me... I can't wait for a Ministro update.

So I found a workaround, I give it here, perhaps this could help someone else.

I have create a APK with Qt lib included, in release mode but not signed.
From this APK, which is in fact a ZIP archive, I've extract all Qt specific stuff:

assets/--Added-by-androiddeployqt--/* lib/armeabi-v7a/libplugins_* lib/armeabi-v7a/libqml_* lib/armeabi-v7a/libQt5* lib/armeabi-v7a/libgnustl_shared

I copy those files on device, into internal storage.
Then, I generate new APK (same configuration: release, with Qt libs and not signed).
To generate the update APK, I remove from this the Qt specific stuff (so APK size is now less than 2MB).
I transfer this APK on device, on device side I insert missed Qt libs into.
Then I start APK installation on device.

This a very dirty way to do it, but it WorksForMe(TM)

@Andy314 There might be some additional custom changes to release build