You can use HP ILO to upgrade its own firmware, by uploading the firmware file (e.g. ilo4_255.bin) via ILO web console. This is straight forward and clear.
But the ILO can do much more (but this is really a bit hidden in the web interface). From the help notes:
So besides the "ILO firmware" (which is quite clear) you can also update the firmware of a lot of other components as well (which was not quite clear to me). This is not really made clear on the ILO firmware page itself. When you go to
Administration > Firmware
you see "ILO Firmware" as title, so it is not apparent to you that you can put many different firmware types in the "File" field.
I tried to update the the System ROM and put the following file in the "File" field:
It indicated that is was uploading the file and then installing it. Then it just switched back to the Firmware page. No result message.
So I checked and I saw that still the old System ROM was installed. Only after I restarted the server, the new version was displayed. Here, the help file comes in handy again: