known bugs of pcb revisions
Level Shifter for 3.3V bluetooth module
affects: MD01_051, MD01_052
fix in: to do
problem: RX/TX lines to the level shifter are swapped
hotfix: make a custom wire and swap RX/TX
pics: todo
pin header K8
affects: MD01_051
fix in: MD01_052
problem: pin header K8 is left of K19. has to be on the right sider of K19.
hotfix: adapter wire