I successfully went from 4.5 OFW to Luma3DS CFW. I used the guide https://www.reddit.com/r/3dshacks/wiki/gateway_a9lh and followed it exactly. After placing the arm9loaderhax.bin in payloads and pressing down on the D-Pad I get a black screen. I can boot to Luma3DS just fine, but not Gateway mode. Then I tried downloading the 3.7.2 GW firmware pack and following the guide for CtrBootManager https://gbatemp.net/threads/tutorial-gateway-ctrbootmanager-setup-auto-boot.407660/ and when going in to the Homebrew channel and selecting Gateway it does the exact same thing, black screen. I am using the old SD card I used for my Gateway back in the day before I changed to Luma3DS. Should I back up the files on the SD card, reformat the SD card, put the files back on and try again (I heard the emunand is on another partition on the SD card) or is there something else I gotta do?