3ds Nand Download Install 'link'

A region change is a more complex use of NAND modifications. It requires tools to modify the "SecureInfo_A" file on the NAND and to install system CIAs for the new region. The process generally involves:

Reinsert the SD card into your 3DS and hold (Start) during power-on. Run the Restore Script: 3ds nand download install

It preserves your strictly unique console identity (SecureInfo_A), which cannot be downloaded from the internet. A region change is a more complex use of NAND modifications