How to know if ATV 2 is flashed??

Hi, I’m just about to purchase a jailbroken ATV2 and the seller doesn’t know whether its been flashed. Is there anyway to tell?

What does the flash actually do to the performance of the machine or is it mainly just so you can run any file type?

Thanks in advance

The surefire way to tell would be to see if there’s a ‘Maintenance’ menu present in the main Apple TV menu. If present, aTV Flash (black) is currently installed.