Information Technology Reference
In-Depth Information
The update process usually works. Successful developers keep separate devices and use them exclusively for devel-
opment. Less successful developers use one device and sync regularly. You often can restore to an older version
and resync. If this doesn't work, you need to wipe the device, reinstall an older version of iOS, and try to resync
again. It's not unusual to lose data when you update, so always sync beforehand.
FIGURE 10.5
Reviewing the available software images. Behind the scenes, this page is really just a list of firmware files. You can
access it in Finder from a contextual right-click menu.
Finding and installing iOS updates
Public updates can be installed via iTunes in the usual way. But beta updates are reserved for developers, and
you must download and install the files manually. You typically update device firmware whenever you down-
load a new beta release of the SDK.
When update files are available, they're listed on the iOS Dev Center page. You must select the correct file for
each type of device; for example, iPhone 4 firmware isn't compatible with an iPhone 3G, any iPad, or any iPod.
To download a file, right-click it and select the Save As… (or equivalent) option in your browser. Firmware files
have the
.ipsw
extension.
To import the file into Xcode, select the Add button at the bottom left of the main window. Navigate to the file,
and select it to load it. This adds it to the list in this window but doesn't install it. Installation is a device-based
process and is described below.
