This is thanks to u/perkel
After Many tries and hours I found this users steps and followed them to success (n3ds). I got through the downgrade process and it automatically rebooted without any problems (no black screen or having to remove the sd).
Here's Perkels solution, and I quote:
"- formated my n3ds (had 10.1, updated to 10.3 then format)
- formated SD (32gb kingstone class10) with SD formater (format overwrite + formatsize adjustements)
- downloaded 9.2-20E firmware for N3DS
-...
What I Believe Is The Best Downgrade Process Right Now
After Many tries and hours I found this users steps and followed them to success (n3ds). I got through the downgrade process and it automatically rebooted without any problems (no black screen or having to remove the sd).
Here's Perkels solution, and I quote:
"- formated my n3ds (had 10.1, updated to 10.3 then format)
- formated SD (32gb kingstone class10) with SD formater (format overwrite + formatsize adjustements)
- downloaded 9.2-20E firmware for N3DS
-...
What I Believe Is The Best Downgrade Process Right Now