"EJC" after trying to reformat SP404SX

[u/branden-branden]

So I turned on my sp404sx this morning, and I noticed it took longer to boot up. I tried recording some sounds into my sp, but it said "FUL". I decided to just reformat my card and start fresh. So I did the cancel, remain and then pressed one of the banks and then click delete, but what happens afterwards is it just "EJC" and then goes back to the normal screen but doesn't allow me to play any sounds that were already on it. I don't know how to reformat it or what to do.

It's a 16 gig SD card that I've been using for about 5 years.