you can play your retail games with emunand without updating your firmware and without a gateway (only if you are on between firmware 4.1 and 4.5) if you are above then this will not work for you, if you are below then you need to update with a game, I suggest Luigis mansion dark moon
(I made instructions on how to do it, just let me find it)
Download the latest gateway 2.2 firmware
open it and enter the "blue card" folder
copy the "GW_INSTALLER.NDS" to the microsd of your DS cart
then run and install the file via your flashcart menu
now take out the 3DS SD card and put into the computer
go back to the gateway 2.2 firmware folder (GW_OMEGA_2.2_RELEASE) and copy "LAUNCHER.DAT" to the root of the SD card
now put the SD back in the 3DS and turn it on
go into setting>other settings>profile>nintendo ds profile
the gateway menu will pop up
go to the right most option and hit FORMAT EMUNAND (this will erase the contents of the SD card so it you have anything important on it, back it up first in your computer) this process will partition 1GB of data for emunand, it is recommended you have a 4GB card
(OPTIONAL) hit the BACKUP SYSTEM NAND button, I suggest doing this just in case something goes wrong
now hit BOOT CLASSIC MODE
you will be back in the 3DS menu, create a folder on your 3DS menu and call it EMUNAND (this way you will be able to tell the two nands apart)
now enter settings and make sure you see the words "GW3D" on the bottom left side of the top screen along with the current version number
if you do not see the GW3D then DO NOT CONTINUE, you will update your real nand
if you do see it then turn on the wifi slider and set up an internet connection via the setting (do not exit the system setting after starting this step doing so will reboot the 3DS and return to the real nand)
then go to other setting and keep going to the the right until you see system update, let it check and update your system when prompted, it will take a while so let it work
after that it should reboot to your emunand main menu (look for the "E" folder your created before to verify)
then go to the setting to see the GW3D 7.1.0-16 version number
now shut off the 3DS and reboot it, the "E" folder should not be here, you can create another folder and call it "SYSNAND" if you want
now go back into the setting and verify your original nand is still on 4.X and then go back into the gateway menu via the profile exploit and select BOOT CLASSIC MODE and you can play what ever retail game you want now with wifi
one last thing make sure to erase any wifi connection settings from your real nand settings and shut the wifi switch off when you are done playing on emunand
this will prevent any updates from being downloaded while on the real nand
)