Trying to update some 7821 phones from sip78xx.10-1-1SR1-4 without CUCM. Setup:1. DHCP server with option 1502. TFTP server3. Downloaded Firmware 78xx.10-1-1SR2-1.zip file. But getting attached error on TFTP server.
No these are old phones. On CUCM I have updated firmware. Wanted to update firmware before connect to CUCM. Also tried to factory reset but same issue.
