Xbox 360 Backwards Compatibility Unlock
By default, Xbox 360 compatibility is disabled on Xbox One. To unlock it, follow these steps:
1. Go to the system menu
2. Press LB, RB, LT, RT in order quickly
3. Select the Developer Console
4. Check the "Enable devkit" box
5. Change the sandbox ID to freezone.reboot
6. Select “Reset Home Console”
Xbox 360 games will now be playable on your console.
Hoax or Fact:
A picture message that went viral online claims to suggest an easy trick to enable Xbox One backward compatibility for playing Xbox 360 games. The picture has the Xbox One logo and has text showing 6 easy steps for unlocking the backward compatibility, which is said to be disabled by default. It is not a fact.
By following the unlocking steps mentioned in the message, any Xbox One user can access the system's dev kit via Developer settings. The trick mentioned in the image was actually faked, and intended to victimize the unsuspecting users into making their next-gen game consoles completely inoperable or bricked. The instructions send the Xbox One into an endless reboot cycle, “bricking” the console; they do not unlock Xbox 360 compatibility.
The question here is, if the backwards compatibility feature did exist within the console, why would it be hidden and not made available? As shown in the video, the code for this unlocking was apparently posted on YouTube by GameTuts, but Microsoft's Larry Herb (Major Nelson) warned users via Twitter to avoid the trick as it can force their device into a boot loop and make the console inoperable.
"To be clear there is no way to make your Xbox One backwards compatible & performing steps to attempt this could make your console inoperable"
Even Microsoft cautioned Xbox One gamers about the ill-consequences of blindly following the YouTube video instructions for unlocking the console through Developer Settings menu.
"Changing the settings in this menu is only intended for developers for Xbox One, and this alone does not turn the console into a development kit. We strongly advise consumers against changing these settings as it could result in their Xbox One becoming unusable. Customers who have put their consoles into this developer setting can revert by restoring factory defaults under Settings / System, select Restore Factory Defaults."
It appears like the prank first appeared on 4Chan website in the form of a fake image posted on Imgur. Users are warned not to believe in such tricks blindly.