Simply just install b9s and luma on sysnand,
boot godmode9 and create emunand and format as gateway,
boot emunand via luma (hold select when booting and tick autoboot emunand), go-to system settings as long as says EMU xx.xx you're on the emunand, s
just update said emunand to 11.12,
The method I posted still works:
https://gbatemp.net/threads/gateway-gw3d-11-10-b9s-and-cfw.550040/
Just install sysupdater with the 5 cia's ( here is the Google search bit.ly/2rheNO2 Go figure the rest )
idk why they manually install updates (with the files i used it's the "updates!" Folder you don't need it) on the other forum (that has the files) this caused a brick which I had to restore via ntrboot when I tried, I simply just booted emunand in luma then used the official update via system settings, then ran sysupdater and just ran the downgrade part which works no need to Manually install the entire update
I found that to be the best method, as you can switch between luma and gateway mode as well as switching between sys and emu nands on the fly, uses the least amount of files, just use sighax+luma to chainload bootct9 using the one .firm payload and the launcher.dat, after downgrading the emunand
My new3ds runs fine with gateway on 11.12-44u, and with my use pretty much has a perfect boot rate, only thing is that eShop will not work correctly on the emunand, your sysnand will have to be updated and I simply use that with luma (untick the autoboot emunand in luma settings) though my sysnand is still at 11.10 (this is why emunands can be useful)