The Solaris installation software and utilities, including the bootadm command, use the presence of the /boot/multiboot and /platform/i86pc/multiboot files to determine if the system's running OS or the Solaris installation software implements the GRUB boot method or the Solaris Device Configuration Assistant boot method.
If the multiboot module from the previous GRUB implementation is loaded by GRUB, the console displays an error message that says multiboot is no longer support and to manually update the entries in the menu.lst file to successfully boot the system. For more information, see http://www.sun.com/msg/SUNOS-8000-AK and the boot(1M) man page.
For instructions on booting a system interactively modifying the GRUB kernel line at boot time, see x86: How to Modify Boot Behavior by Editing the GRUB Menu at Boot Time. For instructions on modifying the menu.lst file permanently after the system has booted, see x86: How to Modify Boot Behavior by Editing the menu.lst File.