I have a multi container project, where one of the containers is a UART datalogger that is going to log data from an external UART device. If the UART device, right now it is a PC with a USB-serial connection, is connected then the RaspberryPi3 will not boot up.
However, if I disconnect the UART TX and RX and cycle the power on the RaspberryPi3 it will boot up and all the containers will work correctly. Then if I connect the UART TX and RX lines it will log the data as programmed.
This same set of programs works fine if I build it directly on a SD card with just Raspbian on it it will boot up and work fine with the UART RX and TX connected.
Does anyone have any idea why having the UART RX and TX lines connected during boot up will cause it to fail to boot?