Just heard from a forum that dstwo can’t work on 3ds but worked well on DS console.
It doesn’t mean the dstwo is defective. I don’t think it’s the firmware problem, so do some updating won’t do help.
Now, here comes a method to solving this problem, just have a try:
Step 1: Download KillDisk and SD Formatter.
Backup your games, saves, media, any of that kind of content to a hard drive, but not the EOS (the /_dstwo/ folder) and ds2boot.dat.
Install Killdisk. Connect your microSD to your computer.
Run Killdisk. Look for the drive that matches it on the left panel of killdisk.
Checkmark Removable Disk with the same file size as your microSD. You should be able to recognize which disk is your microSD.
Right click on it -> Kill Disk.
Choose one pass zeroes, Checkmark verification and type 100 in the box, checkmark Skip disk erase confirmation.
Push start.Wait for it to finish.
Once it’s done, close out Killdisk, and open SD Formatter. Make sure no other flash drives/SD of any type are connected besides your microSD. Go to options, choose format type: quick, and format size adjustment on. Then click format.Now your microSD is as close to new as it can get.
Download EOS 1.11 12-24-2012. This is the latest DSTWO operating system, no patches are needed, all are already included. Open with winrar/winzip/7zip, click on the first folder to go past it, and extract _dstwo folder and ds2boot.dat to your fresh microSD.
Download DSTWO Firmware v1.19
If your card get’s “An error has occurred” when you try to boot it, jump to section 1.A. If your card will simply not start for whatever reason (doesn’t show up on 3ds menu/white screen, etc) or has a Fish Tycoon logo on the DSi/3DS jump to section 1.B. If you can reach the plugin menu somehow, go to section 1.C.
Section 1.A
Open Firmware_v1.19_eng.zip with winzip/winrar/7zip and extract dstwoupdate.dat to the root of your microSD (meaning not in any folders, on the very top level, so it’s path is like microSDDrive:/dstwoupdate.dat After that rename dstwoupdate.dat to dstwoupdateb.dat This is ABSOLUTELY NECESSARY. Then eject the microSD from the computer, put it in the DSTWO, and put the DSTWO in the 3DS/DSi. Boot the DSTWO. Once it hits the “An error has occurred screen” DON’T TOUCH YOUR DS FOR 5 MINUTES. DON’T DO ANYTHING. IF YOU DO SOMETHING YOU COULD BRICK YOUR DSTWO. Once 5 minutes has passed, turn off the console. Connect the microSD back into your computer, and delete dstwoupdateb.dat. Now reprepare your DSTWO for use in the console and see if it works. If it does, congratulations! If it doesn’t, read on to Step 2.
Section 1.B
You will need to find a DS Phat or a DS Lite or a DSi with a very old firmware version. DS Lite/DS Phat is preferrable here. Open Firmware_v1.19_eng.zip with winzip/winrar/7zip and extract dstwoupdate.dat to the root of your microSD (meaning not in any folders, on the very top level, so it’s path is like microSDDrive:/dstwoupdate.dat Boot the DSTWO and when you reach the plugin menu it will ask you to update. If it says 1.19 -> 1.19 then don’t press anything and turn off the DS. You don’t need to do anything. If it says 1.xx -> 1.19 where xx is lower than 19, press A and allow it to update. When it’s finished, turn it off, and insert the microSD into your computer and delete dstwoupdate.dat. Prepare your DSTWO for usage in a console and put it in your 3DS. If it works, congratulations, if not, read on.
Section 1.C
Copy dstwoupdate.dat to the root of your microSD (meaning at the top level, not in any folders). Boot the DSTWO and reach the plguin menu. It will ask you to update. Push yes, and while it’s updating don’t power off or remove the cartridge. When it’s done you can turn off of the system. Now you have the latest firmware. Delete dstwoupdate.dat and read on.
Step 2: Put everything you backed up originally back onto your microSD. (Make sure the files that you backed up do not include ds2boot.dat and the _dstwo folder)
Step 3: Preparing the DSTWO
Alcohol swab the DSTWO’s golden contacts until they are shiny and clean. Let them dry over time, don’t rush it with a drying agent.
Get an air duster and blow air into the microSD port of the DSTWO, across the golden contacts on the microSD and inside the 3DS’s game cartridge slot. Do not put too much pressure into the DSTWO’s microSD slot.
Step 4: Tips to increase the chance of successful bootup
Make sure that SD Formatter formatted the microSD card to fat32 or fat16, you can check by connecting your microSD card to your computer, and right clicking on it’s drive, clicking properties, and seeing what it says next to File System: <type> near the top. It will say fat if it’s fat16. If it’s formatted to something else (ExFat, NTFS, ext2 ext3 ext4 etc) download Fat32Format GUI Repeat the killdisk step in step 1 on your microSD. Then open guiformat.exe, select the microSD drive, checkmark quick format, set allocation unit size to 32768, set volume label to whatever you want to name your microSD, and push start. When it’s done close it out. Repeat the EOS section of step 1. (but not 1.A or 1.B or 1.C) Then try the DSTWO in your 3DS, if it works, do next Step and enjoy.
If the screw on the back on the DSTWO seems loose, tighten it.
Get another microSD, repeat Step 1 with it, (but not 1.A or 1.B), and try again with that microSD card.
Try the following as workaround tricks to fix it but they are not permanent fixes:
Put paper in with the DSTWO to force the DSTWO’s golden contacts closer to the 3DS’s receiver contacts. If it still fails, try more paper. If you get a message saying microSD cannot be read, put small pieces of paper in the outer part of the microSD to push it’s contacts closer to the DSTWO’s receiver contacts.
Push the DSTWO cartridge down a little before and while it’s booting. Not enough to make it click or eject, but just enough to have a balance of pressures.
Boot the 3DS with a regular game, exit with Home, take out the regular game, put in supercard dstwo, boot DSTWO.
