Advance GTA

Unlock All tracks
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Hold L + R, then press Up/Right + B at the Start screen.

Unlock All cars
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Hold L + R, then press Up/Left + B at the Start screen.

Get All tune-ups
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Hold L + R, then press Down/Right + B at the Start screen.

Mini cars
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Hold L + R, then press Right + B at the Start screen.

F1 car
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Hold L + R, then press Left + B at the Start screen.

View credits
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Hold L + R, then press Up + B at the Start screen.