actually in my experience that "hold home at the right time" thing is a bit spurious, just hold down home and then flick the power to reset, you dont need to worry about the timing. just hold it until it reboots. you may need to flick power more than once.
i wasnt suggesting that the packager ever did work for anything other than selecting upgrade from settings, or that s50updater has no relationship with the normal upgrade process. i have been approaching this whole discussion from a "why dont these packages work in recovery or reboot" angle, so i have been making observations about what does and does not happen as a basis for further discussion, and because such observations are pertinent to further progress.
additionally, i've only had a kindle for less than a week. it's the first one i've had, so the behavior of the device is all rather new to me.