Hej,
thank you for your quick reply.

I installed the image on a new SD card but ist still doesn't work. The blue light is shining for about 12 seconds when I hold the on/off switch for about one second (it doesn't come to life if I just tap the switch to the right) and when I charge it with a wall charger (is this the right word?

). But it refuses to start blinking - even with the new SD card and a factory reset.
Maybe the battery is dead? But why doesn't it start when its plugged in the power supply?
Thanks for your support!
xter