WHAT YOU WILL NEED: Braindump - https://github.com/neobrain/braindump/releases Packhack - I couldn't find a link (its at the bottom of the post) NSMB2 (duh) 3DS/New 3DS (With HAX 2.5) STEP 1 (GETTING ROMFS) So the first thing you need to do, is get the actual course files to edit. This is where Braindump comes in. Using braindump is very simple! Just put the folder into your 3ds folder where you keep your apps, select NSMB2, and run it! Please note this does take a while to do. BE PATIENT!! Once you are done, put your sd card into your computer and there should now be a folder called something like "0000007000ae00" or something like that (remember this as it is important for later!!), with your romfs and exefs. Right now all we need is the romfs, so save that to your computer. STEP 2 (EXTRACTING ROMFS) Now that you have your romfs, time to turn that into something we can use! In the packhack folder there should be a application called ROMFS_EXTRACTOR, which is what we are going to use to turn the romfs into a folder. Run it, select a file path, and wait. A common mistake people make is that they click off the program and the save as... window never appears. So just don't click off of it! It only takes like 2 minutes anyways. Now we should have a romfs folder. STEP 3 (EDITING!!!!!!!!) Now do what you want with the files! Edit the levels with Reggie Next or CoinKiller, replace some music, make some textures, whatever. Editing tools: Reggie! Next - https://drive.google.com/file/d/0B_yBl-184usmY2U1ZE5fVkZTZG8/view CoinKiller - http://kuribo64.net/board/thread.php?id=2323 STEP 4 (RE-BUILDING ROMFS) Now, once your finished editing, open up packhack and run the app called ROMFS_BUILDER. Same thing as before, select the romfs FOLDER and save as [NSMB2 Title ID].romfs (I told you that title ID was important!). If there isn't already, make a folder on the root of your sd card called "hans" (no quotes) and put the .romfs in it! STEP 5 (PLAYING!) Put your sd card back into your 3DS, and load up hans. Select NSMB2 and HOLD L while it loads! There should be some options there. Select the one that says "sd -> romfs" or something like that and make sure it says yes. Now, save the configuration and load the game! Whatever editing you did should now be there! Your Welcome! TROUBLESHOOTING If the braindump fails, it probably means that you don't have enough space in your sd card! If you are using Reggie Next to edit levels, put the Unit folder (In romfs) into the courses folder and then click the option "Change Game" in the FILE tab and select NSMB2 if it isn't selected already! It won't work otherwise! While you are extracting or building the romfs, if it gets stuck on "prompting save", that means you clicked off of the program. The only way to fix this, is to go into task manager, find the romfsbuilder/extracter and there should be a drop down menu. Open it and click on the "Save As" prompt window, and save it! WORDS OF ADVICE There is currently no way to edit textures or maps! I will update if I find something! You can open .bcres files with EveryFileExplorer and Ohana3ds Rebirth. You can edit textures with the old Ohana3DS. I am working on a way to edit maps, but I probably won't be releasing it. Also if you have any questions, feel free to ask in the comments!