Hello, I run my seL4 application on 4 core ARMv8. Recently I have developed some more application code (I mention it because file system size is increased an I believe it may change boot time) and from time to time I observed that boot process failed (stuck after the following print) calling schedule calling activate thread kernel boot done.. CPU=1 calling schedule calling activate thread kernel boot done.. CPU=2 calling schedule calling activate thread kernel boot done.. CPU=3 Booting all finished, dropped to user space calling schedule calling activate thread kernel boot done.. CPU=0 Some time I see that only 2 CPU have been booted (like CPU1 and CPU3, or CPU2 and CPU3) Last print is the last one in init_kernel() function Thanks you, Leonid