ROM for executing memory and registers from specific situations.
You can do things like state loading on real machines.

Assemble using nesasm.

nesasm Main.asm

build.bat is available for windows.

Burn to NROM or MMC3 cartridge.
Modify the Mapper definition as necessary to assemble it.

1. Start the cartridge that burned this program.
2. Swap cartridges for the desired game without powering off.
3. Press select button to start game.

Dump each memory from the emulator and change the definition.
Game analysis is also required because it requires an address to restart the program, free memory, and a small amount of programming.
As a sample, defined state to resume from strange map in SMB.

This is running a temporary program transferred to RAM.
It uses memory for the basic 25 bytes and the extra code to return to the game.

• None so far

Removing and inserting the cassette while the power is on may damage the NES main unit.
Use at your own risk.

MIT License.