Iam using the feature (LTE only environment) in NETWORKING>FAILOVER mode FAILOVER - then the settings inside respective WAN connection (in my case its the two LTE connections)
ICMP Ping available
FAILOVER (in an LTE-only environment) to SIM2 is done in MOBILE > SIM SWITCH
ICMP Ping and LCP echo available
I do understand the logic since the RUT12X "place" where this is done can have other WAN interfaces too...(just as the 950) but unfortunatly it blocks me from using LCP echo to figure out if LTE is online or not.