Can I untether atv 2 with 5.2.1 ?

Hi guys I’m new to this so hello everyone. I’ve got an atv 2 with 5.2.1 , I’m forever finding that it freezes with xbmc and I’m having to reboot it by hooking it up to my laptop which is a pain in the arse. Can I possible untether the device?

5.2.1 is tethered and will never be untethered. For your options for untethered jailbreak, you can only go to versions of firmware for which you already have shsh blobs, or that Apple is still signing.

If you do not have saved shsh blobs for an untethered jailbreak version, your only current option upgrade is the 5.3 tethered jailbreak.