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Walkthrough Wednesdays

update phone firmware from TFTP on laptop

I have to deploy several hundred phones quickly to a site that will have a small link back to our TFTP running on our pub.  I am trying to upgrade the phones to the current version of firmware we are running on out cluster.  I have configured a switch (running DHCP with option 150 that is not connected to my network) and a TFTP server and would like to have the phones pull the firmware from the TFTP server that I created.  I have downloaded the firmware files from Cisco.

When I plug in a phone it will get an IP address from the DHCP server and find the TFTP but will not pull the files.  When I look at my TFTP server it says the phone is looking for the file <XMLDefault.cnf.xml>

How can I make this work?


The easier way to do this is to direct option 150 to the appropriate UCM server(s) for this site. There will be a Load Server option on the device-speicific configuration for the phone that you can put the IP address of your local TFTP server in. You can use BAT to add and remove this field if you want. The phones will get their xml configuration files from UCM and then grab firmware from the local load server.

You will need to have downloaded and decompressed the .zip format of the firmware. The phones need the individual files, not the rolled up file you download from CCO.

I would do that but my production DHCP scope will not allow for that many reservations.  This is only temporary.  I would do it out at the site I'm deploying to but it will take a long long time over our WAN for the firmware to download to the phones and I want to ensure that I don't have any issues with the phones once i'm out in this location.  That is why I'm trying to set this up using my TFTP server.

I know it can be done but not sure how.

Yes it can be done and I just told you how. The load server will instruct the phone to pull its firmware from an alternate TFTP server instead of UCM. Add the phones to UCM, set the load server, plug in the phone, wait for it to fully upgrade and register, then remove the load server value from the device configuration. Done.

To use the load server i believe I need to first have my phone registered to a UCM?  These phones are right out of the box and I can't plug them into my production network until they are in the remote location where there home will be.

Then you need to take a crash course on the inner workings of the UCM xml configuration files. This is not documented or TAC supported. The phones look for a series of xml files from UCM to instruct them what firmware they should be running. You'll need to get a copy of this from UCM TFTP, reconfigure the values properly, add them to your TFTP server, and then plug the phone in to the staging network you are using. used to have some information about this that can get you started.


I don't believe the phones have to be registered with UCM to be able update their firmware. We regularly install phones on desks before provisioning via BAT. This way we can confirm network connectivity, DHCP and access to UCM before they go live.

If I recall, to use an alternate TFTP server that is not UCM, you will need the correct *.default.loads file and the necessary firmware files for the phone models on the temporary TFTP server. The correct *.default.loads and firmware files can be extracted from the relevant model and release .zip file at

The only slight change to normal procedure is you may have to perform a factory reset of the phones to force the update.

Hope this helps,


Adam Thompson

Another option for you would be to configure Peer Firmware Sharing. It can be configured for all 3rd Gen phones (7906, 7911, 7931, 7941, 7961, 7970, 7971, etc..). Unfortunately, this feature is not available on 2nd Gen phones (7940/60 etc..)

Take a look at the following link:



Please rate if helpful

Peer Firmware Sharing is great but it is not turned on when shipped from the factory for 79XX phones (only 89XX and 99XX have this on by default). To get it turned on the phone must fully register to UCM once first. This means the first upgrade of firmware can't use peer sharing.

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