How to cancel iOS 7 update in progress?

Leave wifi off. But I imagine you guessed that.

 

At the very least it might download (and take up space on your device unfortunately), but shouldn't install on its own (unless perhaps you restart the phone, which some have said might get it to start installing on its own since it's already downloaded).

 

It will download but wont install until you agree to let it install so you will stay on iOS6 until you let it do it i think.

 

Let it download. Do it with something other than settings in the screen so it will promote you to install or wait until later. Say wait.

If you want to dump the install, back up your phone, erase it on the phone ( don't restore it via iTunes or it will install the update) then restore the backup (which can be via iTunes). Installers aren't backed up so it goes away with the rest of the trash.

 

But even if that works, it would be back once again most likely sooner rather later, unless perhaps you either don't really use Wi-Fi (which isn't realistic for most people) or have your device filled up without much free space (which might be realistic for those who do have it filled up already, or close to it, but also not really realistic or all that rational in general to just fill the device up to stop it from downloading something you don't want to begin with).

 

Fill it up!

Here's what worked for me. I turned on Airplane mode. Went to Camera and recorded a video for about 60 minutes until my storage filled-up (iPad stopped recording the video automatically when it hit that wall leaving me about 23 MB). I turned Airplane mode back OFF and by the time I could get back to the iOS updater screen, it had already failed due to insufficient memory. When I deleted the video, the updater did not resume on its own.

 

Downloading is normal, even if you manually remove it, your phone will download it again.

Until you tap the button to allow the install, it will not be installed.