Cro Tool 3Ds - Gamebrew

Cro Tool 3Ds - Gamebrew
cro_tool
AuthorWulfyStylez
TypeHack Utilities
Version1.2
LicenseMixed
Last Updated2015/09/15
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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.
Marcus Vance
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Marcus Vance

Marcus Vance is a cybersecurity auditor and technology writer dedicated to educating the public about online safety, data privacy regulations, enterprise security, and emerging cyber threats.