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 Sonoclock 890A-Web fails reading the station list #137 To enter update mode, hold down the power
What it did have: Any form of internet connectivity, USB, or flashable memory. The firmware (the internal operating code) was burned onto a ROM chip at the factory. It cannot be altered. To enter update mode