The tool analyzes the game executable ( .exe on Windows, .app on Mac, .elf / .bin on consoles/Android) to detect the target architecture.
YYC games are prone to crashing if the data file and the executable lose "sync." One small change in a script header can break the entire pointer map.
Most GameMaker games use the standard VM (Virtual Machine) export. In a VM export, the game’s code is stored as bytecode within the data.win file. When you run the game, the runner interprets this code on the fly. undertalemodtool yyc
A specific feature within the tool relevant to YYC is the script. For a YYC game, running this script will:
Open the data.win (or game.ios , game.unx ) file as usual. UTMT will still map out the room structures, objects, and sprites. The tool analyzes the game executable (
: Use the texture page editor to add new frames or replace existing ones.
Serious logic changes in YYC require editing the machine code (Assembly) using external tools like x64dbg or Ghidra, then using UTMT to ensure the data file stays synchronized. Using UndertaleModTool with YYC Files In a VM export, the game’s code is
Unlike standard VM bytecode, which is easy to patch, YYC code is rigid.