I figured this will probably be useful to some people, so I thought I'd post it. Using Google, alongside some trial and error, I've created a batch script that can be used to trim all your roms at once. Code: for %%x in (*.3ds) do rom_tool -i %%x | find /i "CARD1" 1>nul && rom_tool -t %%x It will run on all files with the extension 3ds that are in the same directory as the batch file. It will start off by doing rom_tool -i filename.3ds. This command displays the CCI info for the file. Next, it searches for the text CARD1 in the output created by that command. If it finds the text CARD1, it will run rom_tool -t filename.3ds, which is the command for trimming. If the text CARD1 is not found, it will do nothing with the file. This ensures that CARD2 and any future media types will not accidentally be trimmed. To use the script simply copy the code into notepad, then save the file with the extension .bat put this bat file into the same directory as rom_tool.exe, which can be downloaded here. Finally, all the roms you want to trim need to be in the same directory as those 2 files (unless you feel like editing the script to change that).