Hello, sorry for not coming back to you earlier, I did not have access to the oscilloscope until now. The issue is resolved by the folowing commit to the kernel: 108e02b12921078a59dcacd048079ece48a4a983 (usb-ftdi_sio-fix-initial-baud-rate.patch) Applying this as a patch to the kernel solves the problem for me. Thank you very much for your time, Andreas