SUMMARY: How to force a Ultra 1 in 64 bit mode

From: andrea.soliva <>
Date: Thu Jan 09 2003 - 18:42:50 EST
Hi all

Wow many answers with several solutions.....but first thanks a lot to all
who answered! Firstable it must be said that the Open Boot must have the
correct version 3.25 or higher. I use 3.25 and this is OK. Second it is only
recommended to use the 64bit mode if the above Open Boot version is
installed and on normal booting there is a message like following:

Rebooting with command: boot
Boot device: disk  File and args:
NOTICE: 64-bit OS installed, but the 32-bit OS is the default
        for the processor(s) on this system.
        See boot(1M) for more information.

Booting the 32-bit OS ...

This message indicates that the Open Boot version recognize the problem
about 64bit mode or 32bit mode for this processor but on default the 32bit
mode would be booted. It is also recommended to do it only with 200Mhz or
higher. It could be done also on lower speed but it is not recommended.

There are three possibilities to boot the 64bit mode:

First possibility:
Open the file /platform/sun4u/boot.conf and uncommet the last line in this
Reboot the system!

Second possibility:
If the system is running and your are under a shell it could be used:
eeprom boot-file=kernel/sparcv9/unix
Reboot the system!

Third possibility:
If you are under OK prompt it could be used:
setenv boot-file kernel/sparcv9/unix
File being read is under /platform/<uname -i>/kernel/sparcv9/
Reboot the system!

A nice link with the neccessary information is

Ther was no information in the answer to NOT do it about problems. The most
of the answers are saying "yes we do it also and we had never problems". OK
I will do it and by all and many thanks...

Andrea Soliva
sunmanagers mailing list
Received on Thu Jan 9 18:47:07 2003

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