I found the whole soldering action to the test points way to iffy. Alternative idea: Using pogo-pins on a proto board with 40 pin female header - provides the necessary pressure and long term stability as well as +5V and GND. Here used with OPi lite to add an extra USB port for "internal" bluetooth. On the Opi Lite, the test point closer to the CPU is USB D-. If I had a 3D printer, it could also look nicer as the holes for the pogo pins could be more precise :-). Thanks to the Armbian team for including bluetooth drivers in the distro - the whole thing works like a charm.