Legend of Zelda cracked with 6502 assembly language glitch

Find yourself a Famicom and brush up on ancient syntax to finish the game in minutes

A 30-year-old bug in the iconic Nintendo game Legend of Zelda allows players to finish the game in minutes. A video posted to YouTube shows that, beneath what looks to be a fun game glitch, there is a fascinating bit of code manipulation in 6502 Assembly:

Youtube Video

While executing the procedure requires a tediously complex set of steps and manoeuvres, the flaw itself is fairly easy to understand.

The player causes the game to overstep the memory space reserved for drawing sprites on the screen, and in turn to overwrite memory used for other game functions, in effect "breaking" the game and letting the user do things not normally allowed.

This sort of "arbitrary code execution" flaw is the same sort of bug that can be used to jailbreak smartphones or install malware. In this case, it would just be a neat way to impress your friends (provided you still have access to the Famicom 1.1 version, as the NES port does not have the bug present). ®




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