I have 3 different scenarios taking place while trying to deploy Verizon's USB730L USB modems as redundant internet sources on about 20 different RB2011UAS-2HnD models. While all of the mikrotiks are RB2011UAS-2HnD models, some have micro-USB ports and some have full USB ports. For the micro-USB modem, we use a micro to full USB adapter. All routers are running 6.42.5

Scenario 1: Full USB router can see the modem, gets an LTE interface, and pulls an IP. The only issue is that every 2 hours (almost exactly) is that the LTE interface goes down and comes back up. Since I hope for outages to last shorter than that, this is not my highest concern, but any input would be appreciated.

Scenario 2: Micro USB router can see the modem, gets an LTE interface, and pulls an IP. However, the LTE interface drops often. It is seemingly random, but can happen up to 4 times an hour. Furthermore, upon disconnecting the primary internet connection, it forces the LTE internet connection to drop immediately, and doesn't seem to come back at all. This makes the redundancy not work at all.

Scenario 3: Micro USB router can see the modem (via System>Resources>USB), but does not get an LTE interface at all. The modem powers on and shows good status lights.

From a configuration standpoint, I cannot tell what difference there is between Scenario 2 and Scenario 3. However, since the full USB routers have fewer issues, does anyone know of any issues with using USB adapters?

Any help would be greatly appreciated.

I finally found someone else having an issue with a similar Modem: viewtopic.php?t=127343
My modem is a Novatel USB730L, whereas in that post, it is a Novatel750.

The fact that I have fewer issues with the full USB router makes me think this is more of a localized issue than firmware, but is Mikrotik still working on getting these modems working? I believe they only became supported in 6.41.