Impossible to transfer mobile banking app data between factory resets I have two banking apps installed on my device:
https://play.google.com/store/apps/details?id=com.infinum.rba
https://play.google.com/store/apps/details?id=hr.asseco.android.zaba

It is impossible to transfer the app data on the same device between factory resets in a way where it is not needed to reactivate the apps using the activation process of the given banks. I've tried backing up the apps and their data using ES File Explorer PRO and App Cloner Premium. I've also attempted to copy the app data and the apps manually between system to no avail.

Since the device is the same, the IMEI is the same, the operating system is the same, i see no reason that the app data couldn't be reapplied after a factory reset, resulting in a fully functional mobile banking app - however I've found no way to do so, nor have i found which mechanism the apps use that prevents doing so.

Help me out here.
Assuming that the IT department of the bank has implemented some sort of check in their Android app to ensure that you can't restore its data between different installations (which also includes factory resets), they're probably using something along the lines of a unique ID such as ANDROID_ID.

This answer (and specifically Seva Alekseyev's comment) explains what I suspect is causing your issues; this ID also changes on factory resets. This is purely a security measure and a very good one, because it would be terrible if I could log into your Google Play account on my phone and restore your banking app's data from the cloud, allowing me to access your bank account, right?