Normally the only version of firmware still being signed by Apple is the latest. Earlier versions are no longer signed and thus need save blobs to be able to jailbreak.
The general rule is that you can jailbreak earlier versions of firmware if:
EITHER
You already have saved blobs for that version
OR
You already have the desired version of firmware installed on the ATV2 and you use the beta version of SeasonPass with built-in iFaith functionality to extract and save the shsh blobs before trying to jailbreak.
In your case the second condition applies so you should be able to jailbreak.
I just attempted to jailbreak following your and dknight’s instructions using Seasonpass 0.9.2.
When I pointed to firmware 5.2 for the 5.2 version I am trying to jailbreak, I get the following message: “This Apple TV is not eligible for this version.”
A right click on the IPSW box before attending to instructions in the HELP menu (as James instructs) will get the “This Apple TV is not eligible for this version” message.
After overcoming that misstep, my first attempt was a failure despite everything seemingly downloading successfully: The unit booted up without the FC logo confirming the jailbreak. My second attempt proved successful. I’ve jailbroken in the past, but I don’t recall getting the “Your Apple TV 2 has been restored to factory settings” at the end of the process. Thinking that I had successfuly screwed things up, I was prepared to go into the settings and be bummed out to see a 5.3 version. Instead, the unit booted up with the beautiful FC logo icon proudly displayed on the Apple TV desktop.
Version 5.2 jailbroken with Seasonpass 0.9.2 – and with the much appreciated help of dknight and the mod - itimpi. Many thanks to these fine gentleman, and to all who contribute here.