Your Problem just look like mine.
Here is my step by step solution :
1. Format your SD with PC, pick FAT32, do not quick format. ( to check if there is SD's faulty )
2. If format is OK, then copy the EDGE file folder to the SD root.
3. Try to boot your NDS, if you can see EDGE's menu or boot Moonshell, then your EDGE OS is OK ( To verify EDGE OS corrupted or not).
4. Now to copy games, there is two method :
Note : Be sure to extract the game correctly, if you downloaded split ZIP/RAR, they must be unzipped correctly! otherwise the game could not start, even you see there is *.nds extension.
Method A
-Just copy the game to the SD root. ( eg. G:\Ouendan.nds )
-Game can be listed maximum 127 games, more than that, your game is missing on the list. ( EDGE OS limitation).
Method B
-Make a new folder and put it on SD root. ( eg. G:\Funny Games\Ouendan.nds )
-You can make many folders as you like.
-Each folder can only store maximum 127 games, more than that, your game is missing on the list. ( EDGE OS limitation).
-Rare case: if you put the *.nds on the SD root beside the games folder, all created games folder will be missing too. sometimes homebrew will do the same thing.
Mine is 8GB too, sandisk brand. no problem till now, combined with EZ 3in1 and the SD almost full because creating *.sav too much
