Open the non-bootable ISO and locate the isolinux folder. Extract the isolinux.bin file.
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 cucm 12.5 bootable iso download
Official bootable images (e.g., Bootable_UCSInstall_UCOS_12.5.1.10000-22.sgn.iso ) are generally not available for direct public download from the standard Cisco Software Download page. Instead, they are obtained through: Open the non-bootable ISO and locate the isolinux folder
Use a tool like UltraISO to load the ISO and select "Generate Boot Info Table" under the bootable tab. cucm 12.5 bootable iso download
Once you have the bootable ISO, ensure your environment meets these minimums: Cisco Unified Communications Manager Version 12.5