Board STM32F072 Discovery with OpenCM3 ..?

Please could somebody help me to make project for stm32f072rb chip? I am programming it on nucleo board and also on custom HW. I wanted to try platformio but I am a bit stuck with blinky project initialization…

I created sample blinky libopencm3 project, but my board is not supported, so I added this:

platform = ststm32
board = nucleo_f072rb
framework = libopencm3

then I changed nucleo_f072rb.json and added “core”, “ldscript” and “libopencm3” parts there:

“build”: {
“core”: “stm32”,
“cpu”: “cortex-m0”,
“extra_flags”: “-DSTM32F072xB”,
“f_cpu”: “48000000L”,
“mcu”: “stm32f072rbt6”,
“ldscript”: “stm32f072x6.ld”
“connectivity”: [
“frameworks”: [
“name”: “ST Nucleo F072RB”,
“upload”: {
“maximum_ram_size”: 16384,
“maximum_size”: 131072
“debug”: {
“tools”: {
“stlink-v2-1”: {
“server”: {
“package”: “tool-openocd”,
“executable”: “bin/openocd”,
“arguments”: [“-f”, “scripts/board/st_nucleo_f0.cfg”]
“onboard”: true
“url”: “NUCLEO-F072RB | Mbed”,
“vendor”: “ST”

When try to compile it leads to KeyError: Invalid board option build.variant
Is there some other location which I have to modify?

Thank you in advance…