It seems both ebuilds want to install /lib/udev/rules.d/49-stlinkv2.rules At least, when qtstlink2 is already installed, stlink fails to emerge with: * Detected file collision(s): * /lib/udev/rules.d/49-stlinkv2.rules ... * Package 'dev-embedded/stlink-1.7.0' NOT merged due to file collisions. Reproducible: Always