When installing the 2GB memory option (256MB DIMMs X 8), the system
flash prom must be upgraded to 3.2.29 or compatible versions BEFORE
installing the memory option.            

Currently, for Solaris 2.5.1. operating environments, configurations 
are limited to a maximum total memory of 56GB. Configurations that exceed
56GB for this version are not supported.  Solaris 2.6 operating environments,
with patch 105181-19, support a maximum configuration of 60GB.  There is no
limitation for systems running Solaris 7 or 8 operating environments.  When
using Solaris 2.5.1 operating environment, the /usr/platform/sun4u/sbin/prtdiag
command displays erroneous memory capacity information.  Solaris patch 104595-09 
is available on sunsolve.sun.com to correct this problem.            

For additional information, please refer to Sun Enterprise 6500/5500/4500/3500 
System Product Notes, Part number 805-5713-19 or greater.