On our journey towards the next version we decided to buy a soldering oven and give it a try. It enables us to assemble the hardware ourself but we weren't sure if it works especially with BGA components as we use it. After adapting the soldering curve and trying different soldering fluxs our third try works successfully. See the attached pictures. Now the hardware works and even works stable for several days already! The oven has shortens our production cycle and kept the costs down compared to using a vendor for development samples. Of course it only allows us to produce a few pieces efficiently and not larger amounts for production series or extended beta tests. The next steps are to investigate if we can shrinken the hardware even further and of course continue developing the firmware.