Hello Stephan,
Unfortunately we could not rebase the testcase for 17.05 as it is part of my final thesis, that is based on 16.08 and understanding the changes for 17.05 and changing it would exceed my timely scope.
please accept my apology that I cannot follow up on your problem. Given the many current developments, I am unable to justify spending my time debugging problems on an one-year old Genode version, using an outdated kernel and tool chain. I am sorry that this does not help you, but I did not want to leave your last message unanswered.
Cheers Norman