I have disabled the bcm43xx.service and added the dtoverlay=pi3-disable-bt to /boot/config.txt. I understand that is the procedure to remove the bluetooth service that was on ttyAMA0.
My config.txt looks like this:
cpu_mem_1024=256
hdmi_ignore_cec_init=1
disable_overscan=1
start_x=1
dtoverlay=lirc-rpi:gpio_out_pin=17,gpio_in_pin=18
disable_splash=1
force_turbo=1
enable_uart=1
dtoverlay=pi3-disable-bt
dtoverlay=pi3-miniuart-bt
init_uart_clock=39062500
init_uart_baud=38400
dtparam=uart0_clkrate=48000000
^M
#NOOBS Auto-generated Settings:^M
hdmi_force_hotplug=1^M
It appears that non of the above changes have made any difference.
So far no changes made to cmdline.txt in /boot.
The serial connection is being made within a python file and is:
serialPort = Serial("/dev/ttyAMA0", 9600, timeout=1)
This serial connection does open without any error being raised, but no data is received when the following commands happen in the python file:
inbuff = serialPort.inWaiting()
if inbuff > 0:
inStr = serialPort.read(inbuff)
Now this code works perfectly under OSMC running on a RPi2 B. So far no luck on the RPi3 with the latest release.