Problems with firmware downgrading

[michalsabat]

Hello.

I want to downgrade firmware on IP phones from SCCP41.9-3-1SR4-1S to CCP41.9-3-1SR3-1S.

But some phones doesn't want to do that.

On some phones I get "Trust List Update Failed" in Status Message.

Do You have any idea of that problem?

[Sreekanth Narayanan]

Can you check the following:

1. SEP<>.cnf.xml file for those phones to see if they have the lower firmware version specified. You can pull the cnf files from the CUCM server using cmd on Windows (tftp -i <ip addr> get sep<>.cnf.xml)

2. Clear the Trust List from the phones.

3. Try taking packet captures from the phone to see if the CUCM is not responding to the phone with the ITL file.

4. There is an ITLSEP<>.cnf.xml for every phone as well. See if you can pull that too.

[Brian Meade]

Sounds like the ITL is messed up.  Pull console logs and see if it fails to download via TFTP or fails authentication.

Also run "show itl" on all nodes and make sure they all verify successfully.