Well after following a tutorial to get Games to launch on the home screen, I’ve bungled up something and most of my apps wont load. Even Cave story crashes on me.
I replaced an icon .png file, and everything went to heck…
Is there an easy way to reformat my memory card and start fresh?
Yes, you can download the OS image from here: GameShell OS image file
and use something like https://etcher.io to flash your sd card
Bless you!
Would flashing a larger card be problematic?
No but It will appear as 8 GB, then you need to expand the filesystem.
There are posts about that on the forum, I need to find them.
Edit: here it is: GameShell won't recognize my 64gb card
I myself have a 64gb card 
Thanks for the info, and linking this too!
Definitely getting a crash course in Linux learning how to get games working on this little gizmo!
I suggest enabling USB ETH [USB-ETH] How to transfer files if you have unstable wifi
So in the future if you break something, just connect it to the pc by the usb and you can ssh from the usb and fix things up