Android OS update system

Suppose I want to make an Android device with some custom OS modifications.

How could I setup an update system that users could use to get the latest version of my modified Android system for their device?

I can't find anything regarding updat开发者_如何学Pythones in the Android source code.

You may want to check into the update system used by Koush's Clockwork Recovery / ROM Manager. The recovery image is open source, and the ROM Manager's update-format specs and resources are as well (although the app itself isn't). The manager can automatically check for updates from a server and download them in the background, then installs them in recovery mode in one click when the user OKs the update.