MC7455 Rev A: Firmware update not possible

It may not be possible to update the firmware on an MC7455 Rev A (SKU: 1103789) modem.
This modem ships with 02.24.05 GENERIC firmware. If you upload the current firmware (02.33.03), either GENERIC or carrier-specific, the modem will not successfully load the PRI file associated with the current firmware, and the modem will stay in low-power mode.

More specifically, the new firmware will load, but the modem radio will not power up:

FW   1    GOOD   1   0 0      ?_?
FW   2    EMPTY  0   0 0                  
FW   3    EMPTY  0   0 0                  
FW   4    EMPTY  0   0 0                  
Max FW images: 4
Active FW image is at slot 1

PRI  FF   GOOD   0   0 0      002.079_001
Max PRI images: 50

 preferred fw version:
 preferred carrier name:  VERIZON
 preferred config name:   VERIZON_002.079_001
 preferred subpri index:  000
 current fw version:
 current carrier name:    GENERIC
 current config name:     GENERIC_002.026_000
 current subpri index:    000

 carrier name mismatch
 config name mismatch


This was my result after downloading the Verizon-specific PRI. The results was similar when I downloaded the latest GENERIC firmware/PRI combo.

You may be able to successfully reset the modem back to factory setting, but I simply acquired and downloaded the 02.24.05 Generic firmware, and the modem works again.

I have attempted to upgrade firmware in several “Rev A” modems, with no success. I have a Rev B modem that accepts and runs the latest firmware, both Generic and carrier-specific.

I don’t know how to issue a command to the modem to retrieve its “Rev” letter. On my modems, it is printed on the label.

I am writing this to hopefully prevent others from repeating my futile efforts.

Hi @perrysteger
Could you please reach out to your sierra wireless or distributor support person. The modem should accept latest carrier FW. The issue will be better debugged via our official support channel. Thanks.

@joseph I would very much like to work directly with someone at Sierra who can reproduce the problem and hopefully push out a firmware update that will resolve this documented issue with your modems.

I have several “Rev A” modems here on my desk, some still in their anti-static bags. I can send you one of these modems if you’d like. No need to send it back – just looking to help you guys come up with a solution.

Hi @perrysteger
Sure, we’ll be glad to help. From whom/where did you purchase these modems and how many of these Rev As do you have?

Hi @ajoseph:
We have around 100 deployed in the field, and I have five here on my desk. Need to place another order for 100 soon. I have opened up a service ticket with TechShip, and am working with Jörgen Storvist over there. He suspects it may have something to do with the firmware/PRI update software. I’m using fwdwl-litehostx86_64 from the Sierra Wireless website. Downloaded the lite tools within the past month. He asked me to try the Windows one-click firmware update tool, so I’ll try that this afternoon. Thanks again for your offer to help.

Hi, the tools you are using are the right ones. TechShip can open a ticket with us and our support team will assist you. Thanks for patiently working through this.

Hi @ajoseph:

This is a follow up to this thread for anyone who visits here. What I’ve found is that it’s possible to muck with a modem enough to where you can’t successfully upload new firmware and have it pair with the matching uploaded PRI file.

If you revert the firmware to the original firmware on the modem, then the built-in GENERIC PRI file will pair with the firmware and the modem will power up online.

I have since automated our company’s modem provisioning process, and have successfully upgraded the firmware on 8 MC7455 Rev A modems so far. We have many more to go.

I think automating this process is key to reducing the possibility of bricking another modem.

Thanks for your support.