Load your downloaded CUCM 12.5 upgrade ISO into the editing tool.
(Remember: to download official images you need a Cisco account and proper entitlements.) cucm 12.5 bootable iso download
Downloading a bootable Cisco Unified Communications Manager (CUCM) 12.5 ISO requires specific entitlement, as Cisco primarily distributes non-bootable upgrade images on their standard download site Blogger.com 1. Official Download Methods Load your downloaded CUCM 12
A working boot sector file (often extracted from an older valid CUCM bootable disk, like version 11.5 or 12.0). High-Level Steps cucm 12.5 bootable iso download
3. Creating a Bootable ISO from an Upgrade File (Workaround)
sudo dd if=UCSInstall_UCOS_12.5.1.iso of=/dev/sdX bs=4M status=progress && sync