The Installer application may not work on 1.1.2, but the underlying hack certainly does. This could easily be included in any of the Advanced/Extended Preferences packages that have been created to put hidden preferences in the Settings menu. Then you could turn it on or off at will.
Activating the screenshot function is a matter of editing ~/Library/Preferences/com.apple.springboard.plist so that it contains a Boolean value called SBMobileScreenshotr that is set to true (notice the strange r at the end, not a typo!)
One way of doing this is with a plist editor. Another way is with the plutil command from Erica's utilities (an Installer package): in terminal or PuTTY, you'd issue the command
The screenshots are not bad by the way. They are 320x480 pixels, which is the full resolution of the iPhone screen. They are saved in ~/Media/DCIM/999APPLE (as opposed to the usual 000APPLE for pictures taken with Camera), as uncompressed TIF files with 24-bit color depth, 451 kB each. Even on the phone in Camera Roll they look good, but you must first wait for about 45 seconds for the phone to reach the right zoom level.Code:plutil -1 SBMobileScreenshotr ~/Library/Preferences/com.apple.springboard.plist