(The iQue cover photo is because the DS iQue firmware is my “thing” lol)
This guide describes changing the region of your DSi. It basically “clones” the firmware and all files from another NAND. 
this is a very dangerous operation And I don't recommend most people try it. If there is no way to recover from bricking (such as ntrboot), Do not follow this guide
Note – You cannot remove an unlaunch while changing regions.
Prerequisites:
– ntrboot compatible flash cart in case you brick it
– Donor NAND backup for the region you want to install (archive.org is your friend)
– Be an adrenaline junkie (idiot) who doesn't care about the effects of DSi or NAND editing.
Dump NAND:
– Run SafeNANDManager and backup NAND
– Store NAND on your computer, cloud storage, and some thumb drives. You'll regret not taking a backup
Edit NAND:
– Open the target DSi's NAND and delete all folders
To open NAND: nand.bin Open the resulting file with ninfs twl_main.img Use OSF mounts.Please be sure to check Enable write access With either tool.
– Open donor NAND and copy everything to target NAND. **Donor NAND is no longer required**
– Find the launcher ( NAND:/title/00030017/ folder)
– Mark launcher app as read-only
– Copy the attached unboot TMD to the following location: NAND:/title/00030017/484e4141/content/title.tmd
– Mark the unboot TMD as read-only.
– erase NAND:/Shared1/TWLCFG0.dat and TWLCFG1.dat
– unmount twl_main.img from OSFMount, then nand.bin from the nymphs
Flash NAND:
– Copy the edited content nand.bin Save to SD card, Overwrite the first backup
– Calculate the SHA1 hash. nand.bin
– Open nand.bin.sha1 in a hex editor.
– replaces the contents of nand.bin.sha1 Using the SHA1 hash you calculated earlier,
– Save the edited content nand.bin.sha1 Copy it back to SD
– Run SafeNANDManager again. However, this time, select “NAND Restore”.
– Once done, reboot and you're done.
Frequently asked questions:
– The DSi was working initially, but now shows a black screen.
I did not set the unlaunch TMD as read-only. You need to fix it or flash the original NAND backup with ntrboot.
– I can't find the home menu!
I haven't set the launcher to read-only. You need to install a new copy with NTM
– Can't update or connect to DSi Shop!
This is normal. To use them again, you must restore the original NAND backup.
How to use:
HWINFO_S.dat. This file is console specific (contains the serial) and is signed with a leaked key. If you change the contents, the signature will be corrupted and the device will no longer work.
Normally, when you power on your DSi, the stage2 bootloader checks HWInfo for the launcher's title ID. Stage2 has a problem reading a modified or different HWInfo and fails to get the launcher TID. Thankfully, stage2 was programmed to load the “backup” launcher (HNAA/484e4141) if the first one fails. This is a feature left from the factory/prototype firmware.
Placing the unlaunch TMD in the backup launcher location will ensure that stage2 will always be able to boot unlaunch, even if HWInfo is completely corrupted. From there, unlaunch will patch the launcher and fix the HWInfo check, allowing you to launch his HWInfo on another DSi.
It's so easy!
Using this guide, you can actually “clone” your DSi. I cloned the development DSi NAND to several other DSis. It works pretty well! (Obviously there's no real development support, but it's nice to see that all apps aren't removed on startup, as is usual in retail stores.)
It's also a bit weird to have 3 consoles with the exact same serial…
