AsusWRT + 4G/LTE Dongle

Hi,

i'm using an RT-AC56U with latest fw. v378.56_2.

I try to use a Huawei E392 as internet Source. My ISP contract is exclusively LTE connection (no 3G or lower.....only connects in LTE/4G)
But facing some connection problems. It drops connection every time.
I'm on idea that Asus Routers still cant handle 4G/LTE dongles...

Can someone give me some lights to solve this? This router supports 4G dongle connections?

PS: Already tried with another dongle (Huawei E3276), but is...

AsusWRT + 4G/LTE Dongle