Sensor Calibration Screen
A factory menu was discovered in the Game Boy Camera ROM around December 2021 which displays the message, "STORE PLEASE WAIT", then "STORE END" while playing the Run! Run! Run! music. It was first discovered by pressing all inputs (4 directions included) at the same time when booting the rom on an emulator; this can't be easily performed on hardware however. Later on, it was found that filling the SRAM with 0xAA causes the camera to enter the factory menu when next powered on.
In August 2022 efforts to understand the role of save data in glitches with the camera sensor's auto-exposure, resulted in identifying the previously discovered factory menu as a sensor calibration sequence. During this procedure, the camera sensor is activated and the game stores data in the range 0x04FF2-0x04FFF (echoed at the range 0x11FF2-0x011FFF).
Testing the camera in different lightning conditions during the calibration screen and comparing the vector with data extracted from unused cameras (new old stock), it has been established that the data are likely set points or offsets for guiding the auto-exposure of the camera. For an accurate result (matching what is present from the factory) the sensor must be completely covered from light (or placed in a dark environment) during the calibration sequence.
The calibration screen can be initiated by filling the ranges 0x04FF2-0x04FFF and 0x11FF2-0x011FFF of a save file with 0xAA and flashing the modified save back onto the cartridge.
Calibrating your Game Boy Camera Sensor
Method 1 (Factory Wipe Save): Dumped saves from old cameras often have remnants of 0xAA in unused parts of the save file so it is presumed that at the factory, cameras were filled with 0xAA to reset the ram and initiate the calibration sequence. This save is prepared to mimic a factory wipe.
- Use a cartridge reader/writer to backup your camera save data.
- Flash a save file filled with 0xAA onto your camera cartridge using a cartridge writer.
- Place your Game Boy with Camera in complete dark and power it on.
- Wait for the music to end (takes about 10-20 seconds).
- Reboot your Game Boy and enjoy it's fresh calibration, just like out of the factory.
Method 2 (All Unlockables Save): The Game Boy Camera has several unlockable photos in Album B and the JPN Pocket Camera has unlockable CoroCoro themed content which can all be unlocked via save file entries. This save is prepared to expose all unlockable content.
- Use a cartridge reader/writer to backup your camera save data.
- Flash a save prepared with all unlockables and 0xAA in calibration range onto your camera cartridge using a cartridge writer.
- Place your Game Boy with Camera in complete dark and power it on.
- Wait for the music to end (takes about 10-20 seconds).
- Reboot your Game Boy and enjoy all the unlocked content and fresh calibration.