Hallo Hackers, I found (i hope so) the reason for the kbd: sig_sched: invalid ext_preempter in L4-Linux, reported earlier. In file : linux/arch/l4-i386/lib/task.c in function: start_linux_server_thread() is used the variable l4_threadid_t foo_id uninitialized. I set foo_id to L4_INVALID_ID and the sig_sched disappears. But i don't if this is intended from the authors. L4Linux boots now up to tty-init and hangs than. Also the null-pointer test gives an error message. Regards Harald Fritzsche