Hi
hab mal das README in /boot/overlays gecheckt (release stretch)t:
Name: pi3-miniuart-bt
Info: Switch Pi3 Bluetooth function to use the mini-UART (ttyS0) and restore
UART0/ttyAMA0 over GPIOs 14 & 15. Note that this may reduce the maximum
usable baudrate.
N.B. It is also necessary to edit /lib/systemd/system/hciuart.service
and replace ttyAMA0 with ttyS0, unless you have a system with udev rules
that create /dev/serial0 and /dev/serial1, in which case use
/dev/serial1 instead because it will always be correct. Furthermore,
you must also set core_freq=250 in config.txt or the miniuart will not
work.
Load: dtoverlay=pi3-miniuart-bt
Params:
nachdem ich core_freq=250 in die config.txt angehängt habe funktionierte es.
Cheers