This is my suggestion for a sticky topic:
There has been a recent run of MicroUSB cables which cannot be used for Jailbreaking AppleTV devices.
Some USB cables sold as charging cables are not real USB cables, and only have conductors for charging a phone. They cannot be used for data, and therefore cannot be used for Jailbreaking an AppleTV
Some USB cables cannot carry enough current to power the ATV Jailbreak. This can be true of very old cables, which were never designed to be used as a power source, and can also include newer designs with very small conductors, such as a ribbon cable or a very thin cable.
Any cable which is sold with a device that is designed to be connected to a computer for data and power should work. This includes cables sold for or included with Android phones (but not charging-only cables), with updateable GPS devices, cameras, etc. If your cable came with a device that can be connected to a computer to share data and provide power, it should work for jailbreaking.