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:
at!image? TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID FW 1 GOOD 1 0 0 ?_? 02.33.03.00_? 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 TYPE SLOT STATUS LRU FAILURES UNIQUE_ID BUILD_ID PRI FF GOOD 0 0 0 002.079_001 02.33.03.00_VERIZON Max PRI images: 50 OK at!impref? !IMPREF: preferred fw version: 02.33.03.00 preferred carrier name: VERIZON preferred config name: VERIZON_002.079_001 preferred subpri index: 000 current fw version: 02.33.03.00 current carrier name: GENERIC current config name: GENERIC_002.026_000 current subpri index: 000 carrier name mismatch config name mismatch OK
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.