I have to install 40+ IOS devices for my company and iTunes is doing this annoying thing where is keeps "redownloading" the software update with each device and I have to sit here and do nothing for 20 minutes. At this rate, I'll be here FOR DAYS.
iPhone 12
Each model of iPhone has a different software image. If you have iPhone 13 Pro, iPhone 13 Pro Max, iPhone 13, and iPhone 13 mini, despite all being part of the iPhone 13 family, they each have a different build of iOS. Unless you have every variant (occasionally there are different variants based on capacity as well), you will likely see that download.
You may want to look into using a macOS device with Apple Configurator 2 to update multiple devices at once.
Please help, I've been stuck doing this for two weeks!
How do I keep IOS Software Update on my computer?
