Hallo,
first, my ATV is a ATV2 Version with Apple Firmware 4.1.1
ATV Flash is at 1.1
In my Media->Settings I only see GENERAL with Metadata Fetching/Show File Extensions/ Clear Recently Watched and AUDIO with AC3 and DTS Settings.
How can I enable the Grid View Section?
Probably because you are on an old irmware release? I think you need to be on firmware 4.3 or later to get that option.
Yes, aTV Flash (black) 1.0 and later will required AppleTV 4.2 or later.
Your best option will be to re-jailbreak with the current version of Seas0nPass which will install version 4.3.
Thanks for your advice. Thats what I did, but this is another story (jailbreak atv2) 
Now everything works fine!