Inadequate memory for updates

[Henfield]

So I have over 10 gig left and every update says it’s not enough memory. At least the first time around.

It just managed to do the latest update without prompting from me after failing first time around.

What’s gives?

 

[scifan57]

While installing, an update needs almost twice as much available storage as the size of the actual update. This is because the previous iOS version is not deleted until the update is fully downloaded and verified. At that point the update is installed and the old version is deleted.