There are 5 of same IX5000 systems installed on the customer's site.
Recently, We had completed successfully the upgrading OS work from 8.2.3(14) to 9.1.3(14).
But one of five device was not able to complete the upgrading work.
When restart the system, it does should supposed to be entered to the downloading OS screen. but it was not.
The system was completed usual restart process without entering upgrading procedure.
Therefore I thought that the TFTP port (UDP 69) might be blocked, so I checked it out. however there was no problem.
If there was a problem with configuration of the OS image or file quality on the CUCM, it would have failed the all of devices.
But 4 of 5 devices only have been successfully updated.
I would appreciate it if you could advise how to resolve this problem.
CUCM version is 10.5.2.10000-5.
