Just in case somebody need another approach. Had the same problem with PXE rebooting when entering "preparing network connections". I removed and installed several ADK deployments with no success. Solution was simple but not obvious. In the concening tasksquence where multiple driver packages for different computer models included. I forgot to distribute just one of these driver packages to the disitribution/management points. smsts.log gave me the hint. Now PXE works as usual.