Actually, that was the first thing that came to my mind, but it is not related to that because the image does not appear in the viewfinder, when I turn the pop-up screen, the image appears on the screen.  

Check if something is blocking the sensor of the eyepiece, e.g. a strap. An check if the eyepiece appears misplaced.

When I turn on the camera, no image appears on the screen. But when I turn the screen sideways it comes on

Device status   ERROR: smartctl requires a device name as the final command-line argument. I get this error. Is it related? And if I want to download the config, the .zip file is empty...

Hi, first of all: thanks for this really nice project! I set it up with the mentioned rasperry pi 2 zero W and it runs on the system. I used the Waveshare 1.3" oled hat : https://www.waveshare.com/wiki/1.3inch_OLED_HAT It is factory-configured as 4-Wire-Spi with CS0 (based on SH1106). I configured it that way and checked the mark "use display" in the display section. After this first config, it showed "Einstellung gespeichert" (so settings saved, I use the german version) in the display. But since then, nothing can be seen anymore, even after a power cycle, the display stays black. Even saving the config again doesen't trigger a reaction from the display. Any idea what could go wrong here? I could change the jumpers to 3-wire-SPI or I2C, but I don't see how this changes anything since the display already showed text, but only once, so the communication is there ... Thanks in advance!    Niko