Cant get ATV 3. gen into PWNED DFU mode

Hey,

So I have this Apple TV 3. Generation and I wanna use Blackbox. Since mine has the A5 Chip I must use PWNED DFU mode but my flashed pico which worked on the iPhone 4s does not work here for some reason. Do I have to flash another .UF2 file for the Apple TV 3. gen?

Thx