System Administration Guide, Volume 2

What to Do If Rebooting Fails

If the system does not reboot completely, or if it reboots and then crashes again, there may be a software or hardware problem that is preventing the system from booting successfully.

Problem -- A System Won't Boot Because ...	How to Fix the Problem
The system can't find /platform/`uname -m`/kernel/unix.	You may need to change the `boot-device` setting in the PROM on a SPARC system. See "Booting a System (Tasks)" in System Administration Guide, Volume 1 for information on changing the default boot device.
There is no default boot device on an IA system. The message displayed is: `Not a UFS filesystem.`	Boot the system using the Configuration Assistant/Boot diskette and select the disk from which to boot.
There's an invalid entry in the `/etc/passwd` file.	See "Shutting Down and Booting a System (Overview)" in System Administration Guide, Volume 1 for information on recovering from an invalid `passwd` file.
There's a hardware problem with a disk or another device.	Check the hardware connections: Make sure the equipment is plugged in. Make sure all the switches are set properly. Look at all the connectors and cables, including the Ethernet cables. If all this fails, turn off the power to the system, wait 10 to 20 seconds, and then turn on the power again.

If none of the above suggestions solve the problem, contact your local service provider.

SPARC: Troubleshooting 64-bit Solaris Boot Problems

After the 64-bit Solaris release is installed on an UltraSPARC system, the 64-bit kernel will be booted automatically unless any of the following conditions are true:

A FLASH PROM upgrade may be required on an UltraSPARC system before it can successfully boot the 64-bit kernel. Refer to your hardware manufacturer's documentation to determine whether your UltraSPARC system requires a firmware upgrade.
The Open Boot PROM boot-file parameter is set to kernel/unix. If booting the 64-bit kernel fails and this parameter is set, unset it, and reboot the system.
On some UltraSPARC systems, the 64-bit Solaris kernel is not booted by default, even when the system is completely installed with all the 64-bit Solaris components and the correct firmware is installed. Without booting the 64-bit Solaris kernel, 64-bit applications are unable to run.

To find out more about this issue, and how to enable booting the 64-bit Solaris kernel by default, see boot(1m).

You can always discover which Solaris kernel the system is currently running by using the isainfo -kv command.
$ isainfo -kv 64-bit sparcv9 kernel modules
This output means the system is running the 64-bit Solaris kernel.

You cannot boot the 64-bit Solaris operating environment on a 32-bit Solaris system.