Making Bootable Cisco ISO Images

The Cisco Unified Communications Manager ISO on the Cisco Downloads Portal is not bootable; to get a bootable ISO you have to reach out to TAC. Here’s how to make it, and other Cisco ISOs bootable by yourself.

This has been tested on version 15SU4 of Communications Manager (CallManager), IM & Presence, and Unity Connect. It should work for other Linux-based Cisco ISOs.

This is not suitable for production! Use at your own risk. I am using this in my home lab where the stakes are low.

1. Create some tempoary directories to mount the ISO: mkdir -p /tmp/cucm/iso_mount /tmp/cucm/iso_extract

2. Mount the ISO: sudo mount -o loop,ro <ISO> /tmp/cucm/iso_mount

3. Copy the contents over so we can modify them:

   rsync -a /tmp/cucm/iso_mount/ /tmp/cucm/iso_extract/ && cd /tmp/cucm/iso_extract
   

4. (Optional) Modify the hardware scripts to allow running on KVM (only on 15SU4 and later):

   sed -i '/<server_models>/a \           VAL,        *,     *,      *,    *,      *,     *,      *,    *,      *' *product.conf
   

   Explanation: This adds a valid hardware entry that matches any configuraton at the top of the list bypassing all other checks.

5. Recreate the ISO making it bootable:

   genisoimage -r -J -joliet-long -V "CDROM" -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -output ~/OUTPUT.iso /tmp/cucm/iso_extract/
   

   Explanation: -r -J -joliet-long add Joliet and Rock Ridge extensions which use Unicode and allow for long file names.
   -V "CDROM" sets the volume to “CDROM” as the installer looks for the files in /dev/disk/by-label/CDROM:/
   See man genisoimage

6. Recalculate the md5 checksum:

   implantisomd5 --force ~/OUTPUT.iso
   

7. Unmount and remove extracted files: sudo umount /tmp/cucm/iso_mount ; rm -rf /tmp/cucm/iso_extract/

Now you have an ISO that can be booted and installed on any platform.