PR was created: https://github.com/openwrt/openwrt/pull/16070
Latest build: https://github.com/testuser7/openwrt/releases/tag/qualcommax-2540ea6
Request to test this build on MX4200v1/MX4200v2/MX4300.
Thanks to everyone for helping to add support (especially @asd111333). If you have any feedback, feel free to post it here or on github.