u-boot 2022-07 on STM32F746G-DISCO

[Waldemar Brodkorb]

Hi,

I am trying to run u-boot on a STM32F746G-DISCO device.
I am configuring u-boot with stm32f746-disco_spl_defconfig.

I use following openocd command to flash the output of the build:
openocd \
        -f interface/stlink.cfg -f board/stm32f7discovery.cfg \
        -c "init" \
        -c "reset init" \
        -c "flash probe 0" \
        -c "flash info 0" \
        -c "flash write_image erase u-boot-spl.bin 0x08000000" \
        -c "flash write_image erase u-boot-dtb.bin 0x08008000" \
        -c "reset run" \
        -c "shutdown"

The output looks like:
Open On-Chip Debugger 0.11.0
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
Warn : Interface already configured, ignoring
Error: already specified hl_layout stlink
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
Info : clock speed 2000 kHz
Info : STLINK V2J25M14 (API v2) VID:PID 0483:374B
Info : Target voltage: 3.240633
Warn : Silicon bug: single stepping may enter pending exception handler!
Info : stm32f7x.cpu: hardware has 8 breakpoints, 4 watchpoints
Info : starting gdb server for stm32f7x.cpu on 3333
Info : Listening on port 3333 for gdb connections
Info : Unable to match requested speed 2000 kHz, using 1800 kHz
Info : Unable to match requested speed 2000 kHz, using 1800 kHz
target halted due to debug-request, current mode: Thread 
xPSR: 0x01000000 pc: 0x080003fc msp: 0x20050000
Info : Unable to match requested speed 8000 kHz, using 4000 kHz
Info : Unable to match requested speed 8000 kHz, using 4000 kHz
Info : device id = 0x10016449
Info : flash size = 1024 kbytes
flash 'stm32f2x' found at 0x08000000

#0 : stm32f2x at 0x08000000, size 0x00100000, buswidth 0, chipwidth 0
	#  0: 0x00000000 (0x8000 32kB) not protected
	#  1: 0x00008000 (0x8000 32kB) not protected
	#  2: 0x00010000 (0x8000 32kB) not protected
	#  3: 0x00018000 (0x8000 32kB) not protected
	#  4: 0x00020000 (0x20000 128kB) not protected
	#  5: 0x00040000 (0x40000 256kB) not protected
	#  6: 0x00080000 (0x40000 256kB) not protected
	#  7: 0x000c0000 (0x40000 256kB) not protected
STM32F7[4|5]x - Rev: Z

auto erase enabled
wrote 32768 bytes from file u-boot-spl.bin in 0.802971s (39.852 KiB/s)

auto erase enabled
wrote 491520 bytes from file u-boot-dtb.bin in 8.638284s (55.567 KiB/s)

Info : Unable to match requested speed 2000 kHz, using 1800 kHz
Info : Unable to match requested speed 2000 kHz, using 1800 kHz
shutdown command invoked

But nothing happens on the LCD nor on the serial console.
I use screen /dev/ttyACM0 115200 under Linux to connect.

Is ttyACM0 the wrong device to get u-boots serial output?
I have only one USB cable connected between USB ST-Link and my laptop.

What I am doing wrong?

best regards
 Waldemar