It was a late Friday evening. I was at home with my new Canon Rebel XSi, and I was trying pictures of myself. I heard that the EOS Utility that comes with the camera allows to control the camera from your computer through the USB interface. You can only download updates from the Canon website, which require you to have the original media available or an older version of the software installed. I left my original media at work, but I really wanted to use this tool tonight.
After some poking around in the package, I found that inside the package’s update.plist file, there is a node called NeedAppsArray. It has a list of application names as well as signatures. The first item in the list of application names is EOS Viewer Utility which has the signature of CEUX.
With this information, I took a random application in my Applications folder and modified its info.plist file so that the bundle name and OS type creator code matched the values I mentioned above.
After this change, the installer ran without problems. You can get at these plist files by right-clicking on the application and clicking Show Package Contents.