Greetings.
Not having CIMC access means you don't have remote KVM access or ability to power cycle the machine if something hangs during your upgrade.
It is highly advised to do a check of the interop matrix at https://ucshcltool.cloudapps.cisco.com/public/# to confirm the firmware, OS version, along with various storage and nic drivers are on a required version.
If your cimc has worked in the past, and not responding now, it may be running a version prior to 2.03i, which has a fix for memory leak issue, that caused the CIMC to go unresponsive.
Thanks,
Kirk...
