This dongle presents 4G PCUI (Serial interface) and NCM (Hilink) by default and it seems you can't get it to turn off the serial interface (SETPORT AT command).

I also have a Huawei E3131 that presents the NCM/Hilink interface but no serial interface. The E3131 is seen as an LTE interface and works well (although it presents a 192.168.1.x address to the router (via DHCP) which means there is double NAT in place).

The E8278 is not seen as an LTE interface - not sure why this is the case. Perhaps the serial interface is chosen in preference?

Anyone got one of these dongles working?