ATV2 Tethered 5.3 Question

I have a box with 5.3 and it had a tethered jailbreak. For some reason I cannot it to boot tethered again. Since apple is not signing, can I still click on Seas0npass download IPSW. Once downloaded have it upload the file through Itunes. or will itunes fail? So that I can then boot Tethered? What is the best way for me to load this 4.3 tethered as my screen shows apple logo and hangs there. Thank u