cannot jailbreak ATV2

This ATV 2 (was formerly jailbroken) model nr. MC572NF/A with software 6.2.1 on it installed refuses to jailbreak. When I use Seasonpass I get the message that there are critical errors and seasonpass stopsWindows finds device in DFU but while uploading iBECk66apRelesase.dfu gives error entering DFU mode device not supported

Same problem here.

Same problem. Did someone was able to solve it ???