How do you update your iPhone without having it delete everything?

Answer 1

You can't upgrade your iOS on your iPhone without loosing some of your jailbreak. There are some feature (like battery percentage) that are farther in the software and will stay, but Cydia along with most (if not all) of your jailbreak apps will be taken off. You can backup your apps using RockApp, but you loose your data within that app. If/when you update your iPhone you can jailbreak it with RedSn0w then download RockApp again from Cydia and get your apps back, but you may just want to hold off on updating and just stick with what you have.

Answer 2

What kind of iPhone are we talking here lol. And you dont have to delete anything. If you don't have iOS 5 already, you need to plug your iPhone into your computer and update it from iTunes, it's quite easy you should be able to do it no problem, if you do have iOS 5 then you just go into settings on your phone find system update and you can do it straight from your phone, assuming a new update is out that you don't have yet. Note: Both of these may take a couple of hours, so be patient. Also don't unplug your iPhone early if you do it from iTunes or you WILL lose your apps, wait until it is one 100% finished. Just one more thing, depending on how old your iPhone is, you might not be able to update at all, if you have at least a 3GS, you should be fine. Hope this helped ;)