If you are using a DSi system, you can use the homebrew method to open CFW. If you do not have CFW installed yet, I will embed a video below. This video will guide you through installing CFW on your DSi. You WILL need an SD-card for this to work. Remember that installing Unlaunch has a chance of bricking your DSi System. But the chances are minimal.

Please follow this guide to install CFW:

After installing CFW to your system, you will need a firmware dumper. If you plan on using DSi mode on MelonDS, you will need a dumper that supports DSi Nand dumping.

The developers of MelonDS reccomend this Dumper tool. Make sure your dumped Nand has the No$ footer.

Assuming you have dumped the files correctly you should find the following items on your SD-card:
- DSi ARM9 BIOS: 64KB
- DSi ARM7 BIOS: 64KB
- DSi Firmware: 128KB
- DSi NAND image: ~240MB
Now all you have to do is copy these files to a folder in your melonDS directory so you can easily find the files, then configure the emulator.

if instead you want the DS-firmware, you can use this Dumper tool instead. The process is relatively the same, except you will find these files on your SD-card instead:
- DS ARM9 BIOS: 4KB
- DS ARM7 BIOS: 16KB
- DS Firmware: 128/256/512KB
Now all you have to do is copy these files to a folder in your melonDS directory so you can easily find the files, then configure the emulator.

I hope this guide helps! Let me know if you have any questions.
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