SYSNAND-ONLY USERS: DO NOT BOOT GW MODE ON 11.3+ - YOU WILL LOSE B9S AND BE LEFT ON A STOCK FIRMWARE
I highly advise against the use of GW on SysNAND-Only Setups.
GW currently DOES NOT support firmwares 11.3//11.4 - B9S does not change that!
If you're on 11.3+ - Don't even try to use GW. Use Luma3DS or any other CFW that has...
[Tutorial] Using Luma3DS + Gateway on B9S