With the newest update 2.11 there are no more game limits and so far over 600+ roms have been tested with this new update. It also supports folders & pages that it will automatically create and sort games alphabetically. Now in the video below you can see that everything is working fine with 655 games and there are no errors. As of last night when the new update got pushed some people were reporting errors but since then everything has been fixed and working fine.
hakchi2_eng.png (135.41 KiB) Viewed 5970 times
Now it only has 512mb of free space that you can use on the NES mini and would say you could probably get well over 800 roms into it before damaging it. Also always make sure to backup the original kernel before making any changes to it.