Have you done any modifications to something called TWL_FIRM? If not, skip part 1 and go to part 2. If you don't know for sure, start at part 1.

Part 1: To use the Gateway Blue card we need an unpatched TWL_FIRM, otherwise it interferes with the patches Luma3DS uses.
As per Luma3DS wiki:

• Download the NAND Firms package from the Luma3DS wiki here

• From the package, copy O3DS AGB.cia and O3DS TWL.cia (if you have an Old 3DS), or N3DS AGB.cia and N3DS TWL.cia (if you have a New 3DS) to the SD card

• Open your favorite cia installer (the guide has been tested successfully with FBI 2.1).

• Install the .cia files you copied in step 2

• Luma3DS should now be functioning normally

Part 2: Preparing the Gateway Blue card for use

• Go to the Gateway website (Linking it is not allowed) and head to the Downloads section and download the "Firmware GW 3.7.1-BETA “Ultra”" pack.

• Insert your micro SD card for the blue card into your computer. Make sure the card is formatted to FAT32.

• Unzip the downloaded pack and inside you'll find a folder called "Blue Card (R4i)". Copy the "_rpg" folder and the _DSMENU.dat over to the SD card for your Blue Card. You don't need the others.

• Copy any .nds file you'd like to the root of the SD card. (Or create a folder called "games", whatever you like)

• Put the SD card in your Gateway Blue card and insert it into your 3DS.

• Navigate to your cartridge slot and press A to launch it. From there on you can continue to use it as normal

Sometimes the 3DS may not recognise the Blue card immediately. I have found you need to push the card a bit further into the slot and then it will work. Confirmed working as I'm using my Gateway Blue card to play Dragon Quest at the moment on my A9LH Luma3DS N3DS.
Hope this helps!

 

[Tenshi_Okami]

Errr, aren't TWL files Nintendo's code? If it is then you should remove it since its illegal

 

[Temarile]

Errr, aren't TWL files Nintendo's code? If it is then you should remove it since its illegal

I removed them and pointed the link to the Luma wiki

 

[Tenshi_Okami]

There's also this: https://gbatemp.net/threads/tutoria...gb-twl-aureinand-does-this-for-us-now.423155/

it downloads them from the CDN so if the link goes down or something. they can always use that :3

 

[I pwned U!]

@Temarile

Links to the Gateway 3DS website are also not allowed here.

 

[raulpica]

@Temarile

Links to the Gateway 3DS website are also not allowed here.

Removed.

 

[dpad_5678]

Is this essentially the same as bluecardfix.cia?

 

[Temarile]

Is this essentially the same as bluecardfix.cia?

Not really. It aims to do the same thing though: make the blue card work. But this is so you can use it on luma3ds. The blue card fix doesn't work with luma because of the patching luma does.

 

[hegyak]

I wanted to say this tutorial fixed the Blue Gateway Card for me on Cakes.