See also How can I make the CHDK program load automatically at startup?
If you later want to update a CHDK version, just copy the new PS.fir and Diskboot.bin files onto the SD card and overwrite the old ones. You do not have to delete any other file. All settings are forward/backward compatible. After running CHDK and setting all your options for histograms, zebra-mode, OSD (on-screen display) layout, fonts, colors, last script loaded, etc. all your settings are saved in the /CHDK/CHDK.CFG file. It even saves the last position you were reading in the last text-file you were viewing using the File-Reader. If you want to recreate those exact same settings on another SD card with CHDK on it, just copy that file from one SD card to another, making sure it’s in the /CHDK/ folder on the new SD card.
