7912 SIP to SCCP

Answered Question
Oct 8th, 2009


I have a customer who was running asterisk and updated the phone's firmware to SIP via tftpd32 with the firmwares downloaded from Cisco.

My sales colleagues pitched the CUCM idea and he is finally shifting to it. The problem that I am facing is that I can't get the phones to revert back to SCCP. I tried to manually do it from Tftpd32 using a modified gkdefault.cfg, tried erasing the configuration and registering it with CUCM and under SCCP, tried auto registration after erasing the configuration to no avail. The phone seems to be stuck to SIP. There was a single phone that was reverted to SCCP according to my team member but he still isn't sure about how it happened since he converted it back to sip to check the process again and now it's stuck back to SIP.

I would highly appreciate it if someone could guide me as to how to perform this conversion procedure.

The details are as follow,

CUCM 6.1

Cisco CP-7912G

SIP firmware rev, 8.0.1 (060412A)

I have a service contract company login so download firmwares is not an issue.

Kind Regards,


I have this problem too.
0 votes
Correct Answer by Paolo Bevilacqua about 7 years 1 week ago

Yes, exactly. Post the binary file too if you have a chance.

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Overall Rating: 4.7 (3 ratings)
Paolo Bevilacqua Thu, 10/08/2009 - 05:45

gkdefault.cfg correctly generated ? Have you bumped up the revision number ?

You should see the phone dowloading the sccp FW in tftpd32.

muhammadsuhaib Fri, 10/09/2009 - 04:14

The point where you mentioned gkdefault.cfg, I started looking into it and finally found out the mistake I was making.

I have searched the internet far and wide and couldn't really find a solution that handled my problem so I am mentioning the solution here for other people that might be facing or will face this problem.

Attached is the gkdefault.txt file that has all the configurations needed for the firmware upgrade. Once all the modificaftions are made, it has to be converted to binary format for the phone to understand. this is done by the 'cfgfmt' utility with this command.

cfgfmt -tsip_ptag.dat gkdefault.txt gkdefault.cfg

Below are the changes that I made.


The only parts that are relevant are 0x601, 0x080108a and CP7912080004SCCP080108A.sbin

These are the phone model name, the image ID which is taken from the filename of the firmware after the SCCP part nad before .sbin and the firware name.

If all the configurations are done properly then phone will pick the relevant firmware and will upgrade the phone to whichever firmware targeted.

Correct Answer
Paolo Bevilacqua Fri, 10/09/2009 - 04:38

Yes, exactly. Post the binary file too if you have a chance.

You can rate and mark any message at any time.

I did rate your.


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