7841 handset not working

[simc92]

Hello,
We are starting to install 7841 phones from a new stock (CUCM System version is 11.5.1).
It seems that their active load id is sip78xx.14-0-1-0306-175.

We get the 'Inactive Load Failure Reason Internal Phone Error' messagge in CUCM and 'Upgrade Reject: HW compat failure' in the phone's logs.

The phone handset does not work on these new phones, only the speaker.
Could this be related to the load id error?

The oldest 7841 phones already active in our park have this load id 'Active Load ID: sip78xx.12-5-1SR1-4' and they work fine.

Thanks.

[Deepak Kumar R]

Hello simc92,

If the phone was shipped with the firmware version sip78xx.14-0-1-0306-175, then you cannot downgrade to an earlier firmware. Try upgrading one of the 7841 to a later firmware manually to see if that fixes your issue. Otherwise, it could be hardware related. Also check the basics, if the handset wire is plugged properly behind the phone.

[Nithin Eluvathingal]

Hope you connected the headsets on the correct ports. Some users connect them on the Headset ports.

Normally On the phone box, Cisco  mention the minimum firmware version required. If thats matches the load which working phone uses you can downgrade. 

Does the all phones are faulty or few of them ? 

If its just few I would suggest RMA. 

[Les Pruden · Accepted solution]

You are likely hitting a hardware version limitation.  You can see the hardware version by clicking on the IP address of the telephone in CUCM and look at the Device information page. You should upgrade the 78xx firmware to at least Release 14.0(1)SR3.  As always, review the release notes as you might have to install another cop file to support the sha512 requirements -- this is --> ciscocm.enable-sha512sum-2021-signing-key-v1.0.cop.sgn

Cisco IP Phone 7800 Series Compatibility - Cisco

Details

Description :	7811, 7821, 7841 and 7861 SIP IP Phone firmware files only - Compatible CUCM Versions: 11.5(1)+
Release :	14.0(1)SR3
Release Date :	15-Nov-2021