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New Member

Cisco 7940 - hardreset

I have a Cisco 7940 I want to put in our Callmanager.

The problem is it fails to load the Device Default firmware from our Callmanager with an auth failed error.

I want to hardreset it back to factory defaults, but can not get the phone to the part where you can enter the key sequence:

What am I doing wrong ?

According to the youtube video it shows in the display when you have to enter the key sequence

I have tried with 2 Cisco 7940 phone. Same problem.

How do you reset the phone if you are in the Settings menu?

Hall of Fame Super Gold

Cisco 7940 - hardreset

If no display, the phone has been reset already, and is trying to access the firmware files. There maybe no display in that phase.

If you search the forum, tehre are so many threads about the matter of authentication error.


Cisco 7940 - hardreset

Hi Martin,

This probably to do with the firware versions.

The firmware on the CUCM may be to high for the 7940 to

perform a direct upgrade.

You may need to perform an intermediate upgrade from a TFT server.

What version is on the phone now ?

What version is on the CUCM ?



Regards, Alex. Please rate useful posts.
New Member

Cisco 7940 - hardreset

Under Model information on the phone:

Cisco 7940G App Load ID: P00305000400

CUCM under Device -> Device Settings -> Device Defaults->Cisco 7940 SCCP: P00308010200

The phone says the following when starting to upgrade the firmware from the CUCM:

File Auth Fail: P00308010200.sbn

File Not Found.


Cisco 7940 - hardreset

Hi Martin,

Please see this link:-

Signed and Unsigned Images (Image Authentication)
There are two types of images that are used on the Cisco IP Phone 7960 and 7940: signed and unsigned. Image authentication is done through signed binary files. Signed images have a .sbn extension, while unsigned images have a .bin extension.

Image authentication requires that the binary image not be changed prior to being loaded into the phone. Versions prior to 5.x accept unsigned binary files.

Version 5.x and later images accept only signed binary files, which improves security on the Cisco IP Phone 7960 and 7940. However, the use of signed binary files does not allow you to return to an earlier software version. Once a Version 5.0 firmware image is installed, for instance, regardless of protocol, it cannot be replaced with any previous version. The firmware image can be replaced only with another signed image 5.x or later. All versions prior to a Cisco IP Phone 7960 and 7940 Version 5.0 will not load onto the phone after it is installed.

In a previous life it looks like your phone has been upgraded to use authentication files (.sbn)

You will need to load the signed load on to the CUCM TFTP


Regards, Alex. Please rate useful posts.
Hall of Fame Super Red

Cisco 7940 - hardreset

Hi martin,

You are hitting the restriction shown below (as Alex nicely noted +5 "A")

You have 7940's running 5.0.4 trying to go straight to 8.1.2 So you will

need to load an intermediate firmware as a first step.

Installation Notes

Before using the Cisco Unified IP Phone 7960G or 7940G with Cisco Unified Communications Manager release 7.1 or earlier, you must install the latest firmware on all Cisco Unified Communications Manager servers in the cluster.

Note You cannot upgrade to firmware release 8.1(2) directly from firmware release 8.0(10) or an earlier release. You have to upgrade to firmware release 8.1(1) first, then upgrade from release 8.1(1) to release 8.1(2).



Please remember to tag your threads and help support "Teachers without Borders"

New Member

Cisco 7940 - hardreset

We are using CUCM