You know that A9LH you installed? Well. It's installed there. On o3DS an update will just leave you on stock//vanilla. On N3DS you will brick. Thats why you should never update in GW mode.
Okay, thanks for the replies guys, it is really appreciated!If you update your SysNAND on Gateway, you will lose A9LH because Gateway doesn't write protect the firm. So don't do it.
Updating EmuNAND is fine , and updating SysNAN using a CFW that does have FIRM protection like Luma or Cakes will also works.
I have successfully installed A9LH, yay! Just need to set up Arm9Select now, I guess!