While the battery is unplugged, press and hold the Power button and the Light button simultaneously for 60 seconds. This drains every capacitor on the main board.
Why? Unlike a smartphone, the GX3800 runs on closed architecture firmware designed for extreme energy efficiency. Eton Corporation (the manufacturer behind the Grundig brand for this model) did not program a "Code 0000" interface.
: If none of these codes work, check the sticker on the back of the physical unit for a manufacturer-specific code or contact the official support channel via the Grundig User Manual . GX-3800 - User Manual
