How to install SD as Phone Storage? MyPhone Q-Smart LTE

A

AC Question

Hi, I've recently bought an obscure Android 5.1 device by MyPhone (polish company with production in china), called Q-Smart LTE.

The phone is running pretty much stock Android, with just a small sprinkle of bloatware, which I've been able to successfully remove after rooting.

However, the Phone Storage is driving me nuts. Apparently, to punish me for buying an otherwise "ok" phone on the cheap, the memory/storage is made to drive me insane.

Let's off by saying that the manufacturer claimed some 4 Gigs of internal storage, expandable with SDs up to another 32 Gigs. Now, this 4 GB didn't sound bad to me at first, because I was expecting to be able to move the app data to SD, so only a fraction would actually be residing in the internal storage.

Reality, however, turned out to be wildly different. The memory is actually set-up like this.:
- 3.6 GB of Internal Storage, where Apps with no option to "move to SD" are sitting, fair game.
- 500 MB (!) of Phone Storage which acts as SD, in a way that whenever an App would normally be able to move it's data to SD, it lands here.
- an SD Card (from the physical SD slot), which is only accessible for stuff like reading MP3s for the music player, saving down pics and movies from the Camera, and NOTHING else.

Where normally you would have an option to move apps between Internal Storage and SD, I can only move between Internal Storage and this nonsense Phone Storage.
There's a setting under Storage that let's me select external SD card as a default path as opposed to Phone Storage, but it literally only works for saving down the camera stuff. App data (for the "SD enabled" ones) and files downloaded from the internet, all go into this bull**** Phone Storage, which has the crippling 500 MB, so I'm not even physically able to download a game that has more that that much "additional data". This is just absurd.

I've been asking the official support guys from MyPhone, and as you can imagine, their only reply was that this model does not support using external SD for storage (no sh!t, Sherlock).

There must (should?!) be a way to mount and set a physical SD card as a viable storage, not just this music & pics nonsense. A way to swap this crippling Phone Storage with the real SD.
How should I get around it?
Any hints will be greatly appreciated. I've combed the web quite well, but most replies were for people with minuscule Internal Storage (link2SD), or those who were not able to find proper setting themselves. Nothing on my problem, though.
Please help!