On your iphone just go into the settings icon.
Go to "storage and icloud usage".
You will see 2 "manage storage" options, one for icloud and one for storage on your iphone. Dont choose icloud, tap the other "manage storage" choice.
This will show all the apps and storage being used for each. One will show the iphone update. Swipe it and delete. That will remove it from your iphone.