The whole "explain like I'm 5" thing is ridiculous. A huge percentage of topics simply cannot be broken down to an average 5 year old in a way that makes the conversation worth having at all. The 5 year old has no context about why in recent years there has been a huge push towards running your own code on other people's computers using various isolation techniques, or why people are trying to exploit that. The 5 year old has no context for what the exploits actually are, or how to mitigate them. Even if you break all of those things down into 5 year old bitesized chunks, you end up with boring word soup completely disconnected from the meaningful parts of the conversation.

Really what ELI5 is, is a technique to allow the asker to not have to look anything up. From the parent comment, you can look up "patch", "AMD", "microcode"; or you can demand "ELI5!" and have someone else type up long, careful definitions that don't reference context or words that a 5 year old doesn't know.

Regarding what microcode is, here is a good explanation of the differences between microcode and firmware:

https://superuser.com/questions/1283788/what-exactly-is-micr...