Trying to flash MC7354 to generic and use on Cisco 819-4G-VZ, now cisco router will not recognize?

I had two cisco C819G-4G-VZ devices. I am trying to convert one of them to work on T-Mobile network.
First thing I did was updated the IOS to 15.3 800-universal…
Second thing I did was replace the modem with a Sierra MC7354, initally powered up with that modem as purchased off ebay and when I had running it acknowledged the MC7354, but would say mismatch on the fact it was on a VZ 819 and the MC7354. It didnt seem to mind though. When I put my T-Mobile sim in, and configured I got to the point of even getting a IP for cell0 but i was never able to ping out to internet. Strange. Also the cell0 would go down and back up frequently.
I decided to flash the modem using a usb to pcie stick attached to my laptop running a ubuntu live usb since i couldnt get windows to flash the modem, i found a good way to do it with linux. I flashed the modem to a MC7354 generic version, now my 819 modem will not read the modem. It shows no values for it whatsoever. I have since flashed other versions to it, including flashing it to a Verizon version but I still get no acknowledgment from the modem anymore.
What is wrong? Is there truly a need to get the firmware from Cisco, the version that they recommend seems to be avialable on sierra wireless website but am I wrong?
The modem will work on my usb stick just fine with these versions i have flashed. Just not back in the cisco 819… Why?

My goal is to get a 819 working with the T-Mobile network. , Right now I am trying to get the modem to show values for the MC7354 that it did before I flashed it to Generic, I think it had a VZ flash on this one before i changed it…but i have been trying to find a verison that it will read… is it that i must get one from cisco? I dont have a support contract right now, maybe i have to get one…?

Anyone have the answer?


Hi @anthonyingle

You can get the MC7354 firmware at here:

This issue is related to a Cisco device. Please contact Cisco for support in this case.

1 Like