
URGENT READ THIS BEFORE USING IP PHONE SOFTWARE 
-----------------------------------------------

Cisco IP Phone firmware images now contain a
Cisco digital signature to provide authentication for
improved security. Once firmware version 5.0 is
loaded onto a phone, all subsequent firmware
versions will be checked for authenticity.

Firmware images prior to release 5.0 do not contain
a Cisco digital signature and therefore once version
5.0 is loaded onto a phone, all prior firmware
releases will be rejected.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! This means that you will NOT be able to downgrade the  !
! firmware to a release prior to 5.0 once 5.0 or greater !
! is installed onto a phone.                             !  
!                                                        !
! Cisco recommends the following procedure               ! 
! for upgrading to release 5.0 or 5.1                    !
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Upgrading to Release 5.0 and Release 5.1
When you upgrade to Release 5.0 or Release 5.1, you will download 
a ZIP archive instead of a firmware image file as in earlier releases. 
Contained in the archive are the unsigned (.bin) and signed (.sbn) binary 
images. 

Release 5.0 is functionally equivalent to release 4.4. Therefore, we recommend
that you upgrade to release 4.4 first. Verify functionality and that there are
no serious problems in your network. If you have issues, DO NOT UPGRADE to release
5.0. If everything is functioning properly, then feel free to follow the steps
below. By having Release 5.0 be functionally equivalent to Release 4.4, this allows 
you to try the 5.0 content and still have the ability to go back to the firmware
version you are currently using. Once Release 5.0 is installed onto a phone, you
WILL NOT BE ABLE TO LOAD FIRMWARE VERSIONS PRIOR TO 5.0.

Specific information for each release is as follows: 

Release 5.0
Cisco has added image authentication to IP phone protocols, which means that 
tampering with the binary image before the image is downloaded to the phone is 
not allowed. Any tampering with the image will cause the phone to fail the 
authentication process and reject the image. Once you download the Release 5.0 
image, you cannot downgrade to any earlier releases.

Release 5.1
Release 5.1 is the second release of the signed Cisco IP phone image. Release 5.1 
is compatible with Release 5.0 and later. Release 5.1 addresses the user interface 
responsiveness and voice clipping issues. 

Procedure
--------------------------------------------------------------------------------
Step 1   Unzip the ZIP archive to extract the binary images and any notes or 
         readme text files. Read these text files for any special directions 
         regarding the images.

Step 2   Copy the new images P0S3-xx-y-zz.sbn (signed binary) and P0S3-xx-y-zz.bin 
         (unsigned binary), where xx is the release major version, y is the release 
         minor version, and zz is the maintenance number, to the root directory 
         of the TFTP server.

Step 3   Using a text editor, open the configuration file and update the image version 
         specified in the image_version variable. The version name in the image_version 
         variable should match the version name (without the .sbn extension) of the 
         latest firmware that you downloaded (for example, P0S3-xx-y-zz).

Step 4   Reset each phone.

The phone contacts the TFTP server and requests its configuration files. The phone 
compares the image defined in the file to the image that it has stored in Flash memory. 
If the phone determines that the image defined in the file differs from the image in 
Flash memory, it downloads the image defined in the configuration file (which is stored 
in the root directory on the TFTP server). Once the new image has been downloaded, the 
phone programs that image into Flash memory and then reboots. 


For additional release 5.0 and 5.1 information
see the admin guides and release notes located:

SIP:
http://www.cisco.com/univercd/cc/td/doc/product/
voice/c_ipphon/english/ipp7960/addprot/sip/index.htm

MGCP:
http://www.cisco.com/univercd/cc/td/doc/product/
voice/c_ipphon/english/ipp7960/addprot/mgcp/index.htm

