ROM developers create their works in a variety of ways. Some apply their mods to a given base and leave it until the next firmware update, updating only when there’s a bug found. Others update their ROMs mercilessly until every little issue is fixed and everything is perfect. In the latter case, fans of the ROM generally have to download the entire package whenever there may be a minor updates. However, there may be an easier way.
An application by the name of OTA Creator was released by XDA Senior Member thunder07. While we don’t usually promote zip wizardry unless its for learning purposes, this little application can actually be helpful to a number of ROM devs. Essentially, what it does is compare a new ROM with an older version of the same ROM and compare the changes. When the changes have been determined, it creates an update.zip, which can then be flashed in recovery.
As mentioned, this could be useful for devs who frequently update ROMs. Instead of releasing a new ROM every week, devs now have the opportunity to release an incremental update that is much smaller of a package to download and doesn’t require flashing the entire /system partition. While this app was originally posted in the HTC One X section, it should work for all devices.
To learn more, check out the original thread._________