Sometimes when booting, the system will just hang (just stop with no change occuring), as this happens before you have a console it can be hard to diaginose.
OpenIndiana (on x86) uses the GRUB boot menu, this allows you to edit the boot options and add in some arguments that tell the kernel to print whats its doing. If you know GRUB is just a matter of adding -v to the kernel boot line, if you need a bit more help Levent Serinol wrote a blog article about doing it under OpenSolaris, which is exactly the same for OpenIndiana (just replace OpenSolaris for OpenIndiana). Verbose Mode OpenSolaris booting
A usual cause of boot hangs is a driver problem, OpenIndiana allows you do disable any bad driver on booting via the GRUB boot line (same place -v was added). A driver can be disabled by adding -B disable-DRIVER=true to the kernel boot line in grub, where DRIVER is OpenIndiana short name for the driver module
The previous OI148 Broadcom network driver hang, has been fixed and is now in the repo with the rest of OI148. So no workarounds or fixes needed now, should all work out the box.