Your issue seems very similar to this one:
Edit - Check your
[1:] CTRNAND in GodMode9.
1:/
rw/
luma/
payloads/
GodMode9.firm (v1.7.1 - 416.0 KB)
config.bin (32 Byte)
boot.firm (Luma3DS v9.1 - 182.0 KB)
Edit 2- If everything looks in place on CTRNAND, try booting the o3DS without an SD card. If it gives you an error, your issue likely requires
SysNAND Restore (Safe) or
CTRTransfer if you don't have a NAND image.
Lastly, if SysNAND Restore and/or CTRTransfer also fails on you, check for loose flex cables and WiFi module.