Open the non-bootable ISO and locate the isolinux folder. Extract the isolinux.bin file.
To download a , you must typically have a valid Cisco Service Contract or a recent product purchase. Unlike upgrade patches, bootable ISOs are considered full installation media and are restricted to specific delivery channels. Where to Find the CUCM 12.5 Bootable ISO cucm 12.5 bootable iso download
Re-inject the boot file into the ISO and save it as a new file. This modified ISO can now be used to boot a Virtual Machine in ESXi. Installation Requirements for CUCM 12.5 Open the non-bootable ISO and locate the isolinux folder