From memory it was Apple TV 3.0.2. I was the latest version of Firecore.
I just did a Factory Reset and then re-installed ATV flash today and ran the auto updater. So it's up to date as of today. To try and get around the issues, I have unplugged it from the TV and have it plgged directly into the speakers, with sole purpose - plat music. So a bit sad... but hopefully it will behave.
Update: after resetting everything yesterday and installing latest versions of AppleTV and then Firecore, the AppleTV is still misbehaving. For example, it was working fine last night. This morning it won't wake up. I need to pull the plug out and reboot it.