Mini UART on RaspberryPi CM3/CM3+

[Robert Carnecky (Neopsis)]

Did anybody successfully configured Raspberry CM3/CM3+ mini-UART as
the Barebox console? I found a thread
on this list discussing the issue
(https://www.mail-archive.com/barebox@lists.infradead.org/msg35235.html),
unfortunately without any solution.

What I need:

   * UART0 on pins 32/33 (technology access over rs-485)
   * UART1 (miniUART) on pins 14/15 (console)

My current config.txt boots fine my raspberry kernel (zImage built
using builroot):

   kernel=zImage
   enable_uart=1
   dtoverlay=uart0,txd0_pin=32,rxd0_pin=33,pin_func=7
   dtoverlay=uart1,txd1_pin=14,rxd1_pin=15

Now I would like to switch to Barebox as a bootloader. I compiled the
barebox image with

   * CONSOLE_ACTIVATE_NONE = Y
   * 'stdout-path=&uart1;' in  'arch/arm/dts/bcm2837-rpi-cm3.dts' .

and changed my kernel in config.txt

    kernel=barebox.img

I cannot see any output on pins 14/15 e.g. UART1, no barebox console,
no kernel console.
Any idea what's wrong here?

Robert