If the printer is unresponsive, you can force it into download mode by turning the printer off, then for a few seconds before releasing both. Firmware "Fix" (Chip Reset) :
Samsung Printer Reset & Error Code Guides - Farbtoner.com GmbH
: This procedure typically voids the warranty and requires specific data from your device, including the Serial Number , CRUM Number , and current Firmware Version found on a printed Configuration Report. Generating Information Reports