i have similar problem, attached ZTEMF626 to rb2011
It runs properly when I make some changes in modem.
This is because my MF626 have build in microSD card reader, so it have ability to work as pendrive.
I use some AT commands to change some features in it.
I can’t tell what i have don exactly (it was some time ago), but try to disable build in memory IF THERE IS ANY
Twido, thank you for your reply.
After making some changes in configuration of MT (may be turning on UPnP) I've seen it as an USB port:
[admin@MikroTik] > port pr
Flags: I - inactive