I’ve just checked current master, and building with "overlay-usb-nrf-br.conf" worked fine for me. Perhaps you need to clear your build directory?
Anyway, unless I miss something, it should be ok to use pre-built NCP app.
From: users@... [mailto:users@...]
On Behalf Of Nikos Karamolegkos via lists.zephyrproject.org
I am following this https://openthread.io/certification/border-router/device-setup tutorial. So I will USB. However, when I am trying to use "overlay-usb-nrf-br.conf" I have some errors while compiling the zephyr sample (maybe some dependencies are missing - I will check it -). For now I am using the pre-built nRF52840 firmware image (https://openthread.io/platforms/co-processor/firmware#flash_the_nrf52840). Is this problem? In general, the procedure is really simple but I have not managed to make it work