Hi Tomasz,
to debug pthreads it might be worth considering running the scenario on base-linux and attach gdb directly [1]. Even though the ssh run-scripts currently don't support base-linux, I'm pretty sure there is nothing substantial that prevents us doing so, as fork/execve are now supported in linux as well. Maybe all you need to do is change nic_drv and rtc_drv with the linux counterparts and add `ld="no"` to their start nodes.
[1] https://genodians.org/ssumpf/2019-04-26-java-gdb
Best, Sid