In reality there is no such thing as a Pixhawk “Clone”. Technically they’re ALL clones if any one is. Pixhawk was created as open source by Lorenz Meier in 2008. The hardware design is still open source and is still on Githubit for anyone to build. Built by that design source it IS a Pixhawk no matter who builds it. 3DR did for awhile, but never claimed at any point that it was proprietary. Holybro builds their own version today, but they don’t “own” Pixhawk. You, yourself, can build one that meets the design specs available on Github and call it a Pixhawk without infringing any patent or copyright. Just be smart and use quality components.