This may seem silly, but I work exclusively on SPARC boxes, so when I need to get an x86 box into single user mode, such as in VirtualBox, I am lost.
To get Solaris x86 into single use mode:
1. At the “GRUB” boot menu where you get the boot options press ‘e’ to edit the boot line.
2. Use the arrow keys to highlight the line that starts with “kernel”
3. Press ‘e’ again to edit that line.
4. Add ” -s” to the end of that line and press
5. Press ‘b’ to boot
That is it.
FYI, in case you are an x86 guy looking for SPARC instructions, the way to boot into single user mode is to get to the “OBP” prompt and run “boot -s”.
If you are not sure how to get to the “OBP” prompt, run “shutdown -i0” from the command line of a running Solaris box. WARNING! This will shut down Solaris and leave you at the “OBP” prompt, if you are at the console. You will only be able to access the box from the console now. No SSH or Telnet, so make sure you have console access before doing this!