The "Offline" method using the latest CP0xxxx.exe update package is the safest and most reliable method. It handles dependency checks automatically.
Not all older versions are equal. Based on community feedback and HPE change logs, here are the recommended targets: downgrade ilo 4 firmware better
– iLO 4 versions 2.75 and 2.77 introduced memory leaks causing iLO to crash or become unresponsive every few weeks. The "Offline" method using the latest CP0xxxx