Fyi folks just managed to get zte mf833v working with xtrons gs px5 Oreo with actual 4g, NOT RNDIS ethernet (see attached pic)
The way I did it was to place the modem into non-usb mode so that it shows up as a cdc-gsm device.
1: download DC unlocker on your windows pc (this is to get the modem to show up as a COM port)
2: plug your modem into PC and launch DC unlocker as administrator. Select zte modem from the list and leave the rest of the fields on the default auto select. Hit search
3: open up device manager on your PC and look for ports and you should see two COM porta for your zte modem each with a number next to them. Take note of the number next to the one that DOESN'T say diagnostic on it.
4: download PuTy or any other terminal program of your choosing. Connect to the aforementioned COM port using serial connect and if it works well you should see a command line window where if you type AT and hit enter you will get OK as a response
5: type AT+ZDCDRUN=8 and hit enter to place the modem into non-usb mode. If it goes well you should get a message saying updated modem mode or something similar.
Unplug your modem and put it aside for now.
6: if you are using an xtrons unit you need two more things. First you'll need the right MCU as the factory shipped MCU does NOT support cellular network. I've attached the one I'm using to this..make sure you update. Second is you'll need a network settings app to actually enter your APN settings. You can find one on the play store but you won't be able to enter APN settings until you plug in the modem
7: plug your modem In ONLY WHEN YOUVE DONE EVERYTHING ABOVE.
If all goes well it should now allow you to edit your APN. Enter it and hit save then restart your tablet.
I've done some testing with this setup and it takes on average about 20 seconds from start for the tablet to have 4g internet. I toyed around with keeping the modem on a permanently powered usb port but have not been able to keep the connection stable.
Driving around the tablet keeps data signal and switches between cell towers seamlessly.
I do notice that if I turn my car on and off multiple times in succession that can cause the tablet to no longer see the modem. A simple USB reset when that happens does the trick.
Thank you for the info, did you know if that method also working on Android 9 ?