08 April
2016

SIP firmware upgrade path that works with version 9 software

I recently purchased a used Cisco 7970 phone and wanted to
convert it to use the SIP protocol. I did a factory reset and soon
discovered that one cannot upgrade from the factory state
to a recent firmware build without first loading an intermediate firmware.
The problem is that the firmware in the phone validates any new firmware upload before installing it, and it does it using built-in authentication keys. Somewhere along the line Cisco changed the authentication keys used to validate the firmware, and old firmware will refuse to validate new firmware. In between, however, there were a few firmware versions that included the keys for both old and new. SIP firmware versions of those dual-key firmwares, however, are not readily available.

The problem is that while both old and new SIP firmwares can be downloaded for free, the intermediate "bridge" builds and not available from Cisco for free and require a paid Cisco account and I didn't want to get one just for this experiment.

I found a workaround by going through a pair of free SCCP firmwares (i.e. non-SIP software). The following sequence of re-flashes can probably be optimized, but it was faster for me to just go ahead this way.

Upgrading my phone directly to firmware version 8.5 (cmterm 8-5-2SR1) or any newer version led to an "AUTH FAIL" error. Here's what does work:

http://www.dudek.org/blog/blogpics/cisco_auth_fail.jpg
http://www.dudek.org/blog/blogpics/cisco_auth_fail.jpg
(Click to expand)



  • Upgrade to SIP70.8-2-1S
  • This is an old firmware that works on a factory-clean phone. This might not be needed and almost any old firmware is sufficient, but is where I started.

  • SCCP 8.5.2
  • Then upgrade to an old SCCP (AKA skinney) protocol firmware version 8.5.2, available for free from Cisco: SCCP70.8-5-2S (filename cmterm-7970_7971-sccp.8-5-2.zip)

  • SCCP 8.5.3
  • Then upgrade to a SCCP (skinny) protocol firmware 8.5.3
    This is also available free from Cisco. The actual zip package is cmterm-7970_7971-sccp.8-5-3.zip The important point is that this firmware includes the authentication keys for new builds! The corresponding SIP firmware cannot be download for free, incidentally.

  • SIP 9.4
  • Finally, you can upgrade to the free SIP firmware 9-4-2SR1

    Note that if you need to do all this via a TFTP server. For each
    phase unzip the corresponding firmware package, modify the XMLDefault.cnf.xml
    to indicate the loads file to use, and then reboot the phone.


    By Gregory Dudek at | Read (1) or Leave a comment |    
    Comments
    Re: Upgrading Cisco 7970 phones and avoid AUTH FAIL

    Hi, Cisco removed the sccp firmwares for 7970g. Do you still have it lying around somewhere? Would you be able to PM me it? My 7970G is running SIP and i need cmterm-7970_7971-sccp.8-5-2.zip to change to SCCP.

    Thanks!

    [ You didn't leave a contact address. -gd ]

    Posted by: thohawk at September 06,2017 16:48
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