The OS does not boot up on Tecra 8100 (P3-based laptop) because of a problem in FLOPPY.SYS. When this driver is excluded from the build, LiveCD boots up successfully.
I added some DPRINTs to see what is going on in that driver during the OS' startup ("screenshot" attached). It seems like the driver finds a floppy controller and attempts to initialize it. After WaitForControllerInterrupt() is called, the laptop freezes - the call to KeWaitForMultipleObjects() in QueueThread(), that is called by WaitForControllerInterrupt(), never returns.