Flashing SD Card not working

Heya, I just tryed flashing my MCU’s SD card with the script provided by klipper.
This is what I have done:

sudo service klipper stop
cd ~/klipper
git pull
make clean
make menuconfig
./scripts/flash-sdcard.sh /dev/ttyACM0 btt-skr-turbo-v1.4

it all ends with this:

Flashing /home/pi/klipper/out/klipper.bin to /dev/ttyACM0
Checking FatFS CFFI Build...
Connecting to MCU...Connected
Checking Current MCU Configuration...Done
MCU needs restart: is_config=1, is_shutdown=0
Attempting MCU Reset...Done
Waiting for device to reconnect....Done
Connecting to MCU...Connected
Initializing SD Card and Mounting file system...

SD Card Flash Error: Failed to Initialize SD Card. Is it inserted?
Traceback (most recent call last):
  File "/home/pi/klipper/scripts/spi_flash/spi_flash.py", line 1159, in main
  File "/home/pi/klipper/scripts/spi_flash/spi_flash.py", line 1111, in run
  File "/home/pi/klipper/scripts/spi_flash/spi_flash.py", line 1095, in run_reactor_task
  File "/home/pi/klipper/klippy/reactor.py", line 269, in run
  File "/home/pi/klipper/klippy/reactor.py", line 310, in _dispatch_loop
    timeout = self._check_timers(eventtime, busy)
  File "/home/pi/klipper/klippy/reactor.py", line 156, in _check_timers
    t.waketime = waketime = t.callback(eventtime)
  File "/home/pi/klipper/klippy/reactor.py", line 48, in invoke
    res = self.callback(eventtime)
  File "/home/pi/klipper/scripts/spi_flash/spi_flash.py", line 1074, in run_sdcard_upload
  File "/home/pi/klipper/scripts/spi_flash/spi_flash.py", line 910, in configure_mcu
    "Failed to Initialize SD Card. Is it inserted?")
SPIFlashError: Failed to Initialize SD Card. Is it inserted?

and yes it is the right /dev/tty* device and yes the SD card is inserted. Anyone got an idea?

Is it your first time flash of Klipper? You can only use the script if Klipper was already flashed on the board before.

Nope it is installed for about 1/2 a year now