Documentation/reference for fastboot

Where can I find the documentation for fastboot in Android SDK's platform-tools? I know that running fastboot on its own gives a quick help for the different commands, but I'd like to know about details such as: - update: What does *update.zip* need to look like - flashall: Where do the *flash boot + recovery + system* come from, what format, etc. - boot: What is the format of ` and what is the ` option - flash:raw boot: What is the difference to boot and what is it used for I am surprised that in the [Android Developer's Tools Help](http://developer.android.com/tools/help/index.html#) there is documentation for adb but not fastboot.