Showing results for 
Search instead for 
Did you mean: 

7960 switch to SCCP fail with tftp; malformed option in the request



When a 7960 send a tftp request to a TFTP server to load SCCP image, the phone sends a "malformed Packet" in the tftp packet. Currently the 7960 runs a SIP fimware.  Any idea why?


Here is are the files in the TFTP server



Here is what I am seeing in the packet from the wireshark

Trivial File Transfer Protocol
    [Source File: OS79XX.TXT]
    Opcode: Read Request (1)
    Source File: OS79XX.TXT
    Type: octet
[Malformed Packet: TFTP]
    [Expert Info (Error/Malformed): Malformed Packet (Exception occurred)]
        [Message: Malformed Packet (Exception occurred)]
        [Severity level: Error]
        [Group: Malformed]

11 Replies 11

paolo bevilacqua
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

I don't know why Wireshark says so, but these updates normally work for all phones of which possibly millions have been sold.


You didn't answer the question. Wireshark is simply showing what it is seeing. The culprit is the sender (IP Phone 7960).

Do you know why a phone might be sending a 'maloformed' packet?  That is the question that needs to be answered.


What I was trying to tell you, is that I never seen or heard of 79xx phone "culprit" of sending malformed TFTP packets, and I'm doing this since more than 10 years. So logically I have to doubt about correctness Wireshark trace, that doesn't even show why.

I've seen WireShark complain about packets that Cisco IP phones send out. Some would come back to life with a firmware reimage. But I had one which I had to scrap because it wouldn't boot and WireShark claimed the phone issuing duff packets.


Please rate all helpful posts.


Rest assured, wireshark is NOT the issue here. I have a functional SIP firmware on the phone, and am trying to convert the phone to SCCP.  Am suspecting there maybe some option on the SIP phone that needs to be tweaked to get it to send a TFTP packet that is not 'malformed'. 


There are no SIP options to tweak, the phones doesn't even use SIP when doing TFTP.

I recommend you check your TFTP server logs

Paolo - Thaks for your replays. Am not saying we need to tweak SIP options, am suspecting the issue is on the phone firmware itself.  At any rate, it might be that the firmware on the phone is corrupt or has a bug. Wanted to see if any one in the support community expereince something like this, and if they were ever able to resololve the issue....

Got the same issue with a 7911, the solution to the problem is to use a more lenient tftp server. Have not dug in what makes the tftp request "malformed" but many tftp servers choke on them as does wireshark, and the phone does not get what it wants.

See for a longer description.

Paolo - Just because you've never seen one, doesn't mean it couldn't happen.  Malformed can be formed for many different reason,  just wanted to know why here. 

With much respect to your experience, ofcourse.


Hi Matt.
An old similar post can be found here


Sent from Cisco Technical Support iPhone App

Please rate all helpful posts "The more you help the more you learn"


I saw the old post. It didn't aswer the question or resolve the issue.

The questions is, how can you make the phone NOT send malformed packet?

The phone runs Fimrware versions: App Load - P0S3-04-1-00 & Boot Load PC03A300

It is working fine as a SIP phone.


Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Recognize Your Peers