However, to install precompiled firmware on a PowerShot camera, it is only necessary to download the correct binary and copy it to an SD memory card. If the SD card is set to lock and the boot flag is enabled when the camera is turned on, the camera will autoboot from the binary file on the card and CHDK will be loaded into the camera's RAM. If the card is unlocked or removed, the camera will start up in the original Canon firmware. CHDK will mask the lock on the SD card so that the camera will still write to it however. Alternatively, CHDK can be loaded manually from the Canon menu.