35.4MB???? My iPhone 5S says I need 1.2GB free for installation, I only have 500MB (out of 32GB)![]()
This is the error message I get:
Keep in mind the update is 35.4 MB.
It probably only needs it temporarily for moving files around. My only guess is that updates patch iOS by copying the old files to a new directory, patches them, makes sure they were patched right, then deletes the old files and replaces them. In this case the 35 MB would actually contain patches to several files totaling ~1.4 GB spanned across the OS, which all need to be duplicated before shoving the 35 MB of data in.
Convoluted? Yes, but it helps ensure smooth updates and iOS isn't the only one to do this.
Disclaimer: My conclusion is an educated guess at best, and it's details may be a bit fuzzy.