Hi, I am Christoph, an independent advisor for Windows questions, ready to help you solving your issue. From what I understood is you can't access the folder for your iPhone updates. Please press Windows key + R simultaneously and type in %appdata% followed by the ENTER key. This should lead you to your AppData\Roaming folder. You should find .ispw files located following "Apple
Computer\iTunes\iPhone Software Updates" which are indeed updates for your iPhone.