1.Plug your USB flash drive into a USB port on your computer.
2.Download the update file.
3.Click Save to save the console update .zip file on your computer.
4.Unzip the file. If you are using Windows XP, Windows Vista, or Windows 7, double-click the .zip file to unzip it.
5.Copy the contents of the .zip file to the root directory of your flash drive.
6.Unplug the USB flash drive from your computer.
7.Plug the flash drive into a USB port on your Xbox 360 console.
8.Restart the console.
9.When the console restarts, the installation program starts automatically. Select Yes when you are prompted to update the new console software.
Just for the people who cant wait for update , hope this helps you in future!
I think I’ve figured it out, I’m almost 100% sure slims get it first. All of my friends that do have slims got the update and all of those that dont still have not got it.