Easus doesn't format your SD properly.
If you have another one (even a 2Gb one will do) copy the arm9loaderhax.bin to it and the luma folder.
Get the latest emunand9 from GitHub (
https://github.com/d0k3/EmuNAND9/releases/latest ) and put the emunand9.bin in your payloads folder ad rename it to y_Emunand9.bin.
Boot your console while pressing Y and emunand9 will launch.
Go to SD Format Options, Format SD <No Emunand> Press B (No) for starter.bin and swap your SD with the one you need to format.
Let it do it's thing and when finish, press SELECT to eject the card and copy back your SD backup to it.
Insert your SD on console and press B then START and everything will be OK.