When there are multiple iPhones in a household and you want to upgrade them all from a single iOS download via multiple Macs, it can be a bit of a challenge. I have previously blogged about how to do this. This post contains the link to the latest version of iOS for the iPhone 4.
Using a proxy
I again used Charles to capture the url of the iOS 4.3.2 firmware update file (.ipsw). I had to enable the SOCKS proxy options this time to capture the traffic successfully.
Enable the SOCKS proxy in Charles by clicking on Proxy > Proxy Settings in the menu and checking the Enable SOCKS proxy checkbox in the Proxies tab.
Also check the Use SOCKS proxy in the Mac OS X tab.
The iOS 4.3.2 firmware update file (.ipsw) that iTunes was downloading is clearly visible in Charles:
Update each iPhone as per my previous post.