Cro tool 3DS

cro_tool
General
Author	WulfyStylez
Type	Hack Utilities
Version	1.2
License	Mixed
Last Updated	2015/09/15
Links
Download
Website
Source

This tool is used to allow the modification of CRO libraries on 3DSes under FIRMs with PS:VerifyRsaSha256 patched in some form. On pirate CFWs, this is patched already. ARM11-based hacks which allow for romfs-file replacement won't work with this.

This is done by rebuilding hashes for each CRO file, then rehashing and resigning the CRR file based on those. A static RSA key is used for signing, since a hash of the latter half of the CRR must be signed even with VerifyRsaSha256 patched.

User guide

To use, put cro_tool in a folder with all CRO files from the target application.

Afterward, just use cro_tool [-v] static.crr or drag-n-drop static.crr onto cro_tool.

An invalid Nintendo signature is the intended behavior after resigning a crr with this tool.

Changelog

1.1

• Do hash verification how RO does it (just ensure the hash exists in the CRR hashtable, position-independent).
• Scan for cro files instead of user-specifying them.

Credits

Thanks to 3DSguy and neimod for ctrtool, which this tool was hastily built off of.

External links

• GBAtemp - https://gbatemp.net/threads/release-cro_tool-cro-resigner-for-rom-hacks-etc.395148