here's the link : http://www.rfactory.org/OpenWRT/index.html

make sure u download the last group under the red color warning words,. ( that's the latest one )

and flashing to openwrt/ddwrt, can give stable wifi connection, many other function like modem detail, network status,. QoS, dns forwarding, and so on,..

mine is MR11u V3 convert to MR3040 V1 oipenwrt firmware ( for yours u download the MR3420 V2 version )

[attachmentid=3388009]

u flashing the openwrt barrier breaker or ?

restart your router again, it should be auto detect and connect all time 

Go settings, did you tick bring up on boot

Tick it

Did it get detected when you power cycle?

Or try use the reboot in the router

what usb modem u are using ? 

both of those model should be auto detect and auto dial connection,..

which openwrt bb u download ?

it is under the warning experimental or above ? 

Use MDMA

MR3420 v1 dont supoort LTE on stock firmware

If you lock band to LTE only, this is what's going to happen.

LTE towers are rare in Malaysia and could possibly be conjested most of the time. If your modem is allowed to "float", when connection cannot be made to the LTE tower due to conjestion, a second tower will be used, and so on. But because user forcing connection ONLY to LTE towers, the modem will always wait for connection to the specific tower, even though there could be other (non-LTE) towers lying around.

Don't use band-locking unless there're many LTE towers in the area, and that their signal is good enough. Just my $0.02.

How about back to stock firmware

What do you mean?

Use MDMA while modem connected to the router?

I guess Rooter firmware got a set of diagnostics tools which is fairly similar to MDMA

Possible but not practical.

Mind telling why you want to do it at first?

Have you already used the Rooter Firmware?

MR3420V1 is incompatible with LTE