upgrading First Generation AppleTV - aTV flash??

[ManOfTheForest]

Has anyone here used aTV Flash?

I have an old first generation AppleTV. I'm giving it to my sister and I'm currently loading it up with TV shows and movies I have purchased - cartoons and such for her kids.

They love science and nature documentaries and I have quite a few in various formats like mp4, FLV, etc,. that won't play on an AppleTV.

I was searching to see if their was anyway I could load them up or a way to get Plex on the old AppleTV and I found aTV Flash. I don't yet understand how it works or how to install it but I was just curious if anyone else has done it.

Is it reliable -- I saw one comment that it stopped working after a few weeks?
Is it safe to use - any issues with security on the iTunes account?

Any info is most welcome or even if you guys have alternative ways to different video formats onto the first AppleTv.

Regards