firmswap

My Python 3 implementation of the hardmod downgrade for Nintendo 3DS.

Yes, I know Python isn't the best language for this (something in C could probably run in a second or less), but it works and it's all I know.

Default behavior

• Create backup of NAND.bin named NAND.bin.bak
• determine if NAND.bin is for New3DS/Old3DS
• read FIRM0FIRM1 partition
• xor FIRM0 with firm_110_<model>3DS.bin and firm_104_<model>3DS.bin
• write to NAND.bin

firm_110_<model>3DS.bin and firm_104_<model>3DS.bin should be extracted from decrypted 11.0/10.4 FIRM CIAs ExeFS.

Usage

python3 firmswap.py [options]

• --nandimage=<file> - use instead of default NAND.bin, backup file will be filename.bak
• --nobackup - do not create a backup of NANDimage
• --firm110=<file> - use instead of firm_110_<model>3DS.bin
• --firm104=<file> - use instead of firm_104_<model>3DS.bin
• --swapfirm1 - xor FIRM1 partition in addition to FIRM0
• --forcenew - assume NANDimage is for New3DS
• --forceold - assume NANDimage is for Old3DS

License

firmswap.py is under the MIT license.