Solaris 220R init 6 hang

If you run init 6 on 220 and it hang, and you have to hard reset to reboot the system. This is what you should do. This system must have single cpu and it is installed on slot/module 2. Move it to slot/module 0 to solve the issue.
Example below with 220R with 2 cpu's for illustration
:~$ /usr/platform/sun4u/sbin/prtdiag
System Configuration: Sun Microsystems sun4u Sun Enterprise 220R (2 X
UltraSPARC-II 450MHz)
System clock frequency: 113 MHz
Memory size: 1024 Megabytes

============CPUs ===========

Run Ecache CPU CPU
Brd CPU Module MHz MB Impl. Mask
--- --- ------- ----- ------ ------ ----
0 0 0 450 4.0 US-II 10.0
0 2 2 450 4.0 US-II 10.0