Note: This stuff worked for me. If you're afraid you'll brick your card, maybe you should just stick with the default firmware.
I just bought an IBM M1015 RAID controller for my ZFS server, as the old Intel SASUC8I did not support drives bigger than 2 TB. This IBM controller is usually available really cheaply on ebay.
It comes with a fairly basic RAID firmware that'll do mirrors or stripes, but no RAID5. Supposedly, it should hand off non-raid drives transparently to the OS, but i wanted to load the LSI IT firmware that turns it into a dumb HBA instead. This is my process.
I've just wasted quite a bit of time debugging a problem and google is less than helpful with the search terms i used. Here's hoping this will attract it - and at least i'll be able to find it myself :)
If you try to "ssh -X" and the remote end doesn't set $DISPLAY, it's probably because you're missing xauth on the server.
I've been using this solution since the time 8.0-RELEASE was still just a wet dream and other than the lack of the recover-during-install option from a local drive, it's been rock solid.
As you're probably aware (since you're reading this), some of the new hard drives with "Advanced Format" lie about their sector size and thus the partitioning and/or file systems end up unaligned with the disk and performance suffers. Boo, Western Digital. You guys are worse than Hitler. But, since the WD20EARS was cheap and i didn't think anyone would design something so stupid, i bought it.
Ofcourse, ZFS is smart enough to use the larger sector size through the "ashift" setting, but only if it actually knows the sector size of the drive. This option is set at pool (or rather VDEV) creation and can't be changed.