The halt is similar under OpenVMS and Tru64 UNIX, in that an XDELTA not loaded message is displayed.  The solution is to issue an INIT command at the console prompt to clear the problem.    The example below depicts the problem during an OpenVMS boot.

>>>b
(boot dka0.0.0.6.0 -flags 0)
block 0 of dka0.0.0.6.0 is a valid boot block
reading 904 blocks from dka0.0.0.6.0
bootstrap code read in
base = 1f2000, image_start = 0, image_bytes = 71000
initializing HWRPB at 2000
initializing page table at 1e4000
initializing machine state
setting affinity to the primary CPU
jumping to bootstrap code
 
   OpenVMS (TM) Alpha Operating System, Version V7.1
 
ff.halt code = 5
HALT instruction executed
PC = 110678
fe.fd.fc.fb.fa.f9.f8.breakpoint at PC 1108e0 desired, XDELTA not loaded
f7.f6.f5.
ef.df.ee.ed.ec.f4.eb.ea.e9.e8.e7.e6.....e5.
V7.0-9, built on Mar 18 1999 at 13:25:37
>>>