Grundig released a web-based configuration tool for later models like the (circa 2008), which connected to Wi-Fi and allowed firmware flashing via a PC web browser. Search engines conflate the model numbers. If you type “Sonoclock 890 firmware,” Google may show results for the 890’s successor without clearly distinguishing them.
If you typed into a search engine, you are likely one of three people: Grundig released a web-based configuration tool for later
To enter update mode, hold down the power and specific navigation buttons while plugging the power supply back in; the screen should display " USB Upgrade Grundig released a web-based configuration tool for later
