ntool

Requirements

• Python3
• pycryptodome: pip install pycryptodome

Usage

• For the example commands, those in brackets are optional
• Use python instead of python3 if using Windows

Notes

• "SRL" is equivalent to a .nds/.dsi file; "CCI" is equivalent to a .3ds file
• A ROM resigned for dev needs to match your devkit's region for it to load successfully
• IS-NITRO/TWL does not emulate Slot-1 save memory. Most games will show an error message if the save memory is not present. To work around this, you will need to insert a Slot-1 card with a matching save memory chip before loading the ROM image.

Re-sign and re-encrypt NTR/TWL-enhanced/TWL-exclusive SRL for dev:

python3 ntool.py srl_retail2dev <path_to_srl> (--out <path_to_output_file>)

Re-sign and re-encrypt CIA/CCI for retail/dev:

python3 ntool.py cia_dev2retail <path_to_cia> (--out <path_to_output_file>)
python3 ntool.py cia_retail2dev <path_to_cia> (--out <path_to_output_file>)
python3 ntool.py cci_dev2retail <path_to_cci> (--out <path_to_output_file>)
python3 ntool.py cci_retail2dev <path_to_cci> (--out <path_to_output_file>)

Run dev firmware on a retail 3DS (with Luma3DS)

• WARNING: Only perform this on SysNAND if you are able to use ntrboot to recover from a brick!
• First, obtain the SystemUpdaterForCTR zip file from NDP if you have a o3DS/o3DS XL/2DS. For n3DS/n3DS XL/n2DS XL, obtain the SystemUpdaterForSNAKE zip file instead
• Extract the zip file, and choose the appropriate .csu file for your 3DS's region
• Run python3 ntool.py csu2retailcias <path_to_csu>
• Place the updates_retail folder in the root of your 3DS's SD and rename it to updates
• Install sysUpdater, launch it and follow the on-screen instructions
• You may need to enable Set developer UNITINFO in Luma3DS settings

Convert CCI to CIA

• Pass --cci-dev if the CCI is dev-crypted/signed, pass --cia-dev if you want to build a dev-signed CIA

python3 ntool.py cci2cia <path_to_cci> (--out <path_to_output_file>) (--cci_dev) (--cia-dev)

Convert CDN contents to CIA

Example folder structure required:

cdn_folder/
|__ 00000001
|__ 00000002
|__ 00000003
|__ tmd.0
|__ tmd.16

• If --title-ver is not provided and there are multiple TMD versions in the CDN folder, the latest TMD will be used
• If a cetk exists in the CDN folder, it will be used as the ticket; if not, a ticket with a fake signature will be generated and used
• Pass --cdn-dev if the CDN contents are dev-crypted/signed, pass --cia-dev if you want to build a dev-signed CIA

python3 ntool.py cdn2cia <path_to_cdn_folder> (--out <path_to_output_file>) (--title-ver <ver>) (--cdn-dev) (--cia-dev)

Convert CIA to CDN contents

• Pass --titlekey to use a custom titlekey to encrypt the content files (this field will be ignored if the ticket in the CIA is signed)
• Pass --cia-dev if the CIA is dev-signed
• Note that clean CDN contents are not guaranteed as the CIA may have improper contents (e.g. due to being decrypted)

python3 ntool.py cia2cdn <path_to_cia> (--out <path_to_output_folder>) (--titlekey <titlekey>) (--cia-dev)

Full extraction and rebuild of NCCH/CIA/CCI:

• First, use ncch_extractall/cia_extractall/cci_extractall to extract the NCCH/CIA/CCI to a folder
  • Pass the --dev flag to use dev crypto
• Next, modify the files in the folder as necessary
  • Note: do not modify the exefs.bin, romfs.bin, or .ncch files directly; modify the extracted contents
• Then, use ncch_rebuildall/cia_rebuildall/cci_rebuildall to rebuild the NCCH/CIA/CCI.
  • Pass the --dev flag to use dev crypto

python3 ntool.py ncch_extractall <path_to_ncch> (--dev)
python3 ntool.py ncch_rebuildall <path_to_folder> (--dev)
python3 ntool.py cia_extractall <path_to_cia> (--dev)
python3 ntool.py cia_rebuildall <path_to_folder> (--dev)
python3 ntool.py cci_extractall <path_to_cci> (--dev)
python3 ntool.py cci_rebuildall <path_to_folder> (--dev)