After the Nikon D5100 firmware was decrypted and we got the first unofficial “Star Wars” firmware update, there is now a full hardware emulator including screen visualizer for the Nikon D3100/D5100/D7000/D* cameras that uses the Fujitsu FR MIPS processor. This will enable anyone willing to write custom firmware routines and then test them without risking their hardware being turned to bricks. See this related flickr discussion and this forum post for more information.
