I have got a Everdrive which is firmware 8 and OS 23. It is running on a CDX. It is using a 2GB Sandisk SD card. For the ROMS, I have directories sorted into regions (Europe, USA, Japan etc...) and then alphabetically, but for some reason the sub folders of the regions are only showing letters B C and R on the console. (Should be A, B, C, D, E, F, G etc...) Plug the SD card in a PC and all directories are showing. I have tried reformatting the card on the MD and copying the folders back, but the same thing has happened. Only B C and R are showing. Does anyone have any suggestions please?
When I put my games on the card I noticed it didn't seem to work at all to have two folder deep directories. In other words at the root of the SD card I have folders with the roms like A-F, G-P, etc. At first I tried having MD and SMS folders with letter folders in them but for whatever reason it just didn't like it. So I recommend again doing what you are probably doing which is putting every single ROM in the GoodGen set on your EverDrive at once. It's better to just put the games you actually will PLAY on your SD card. I have no idea why the EverDrive has problems when you overload it with folders and rom files.
I have every game in goodgen on my sd card and have zero problems. I have 2 folders in my root. 32X and Genesis. Then under each folder I have the roms separated by folders A, B, C, D, E, etc. No problems what so ever.