5.2.1 p9 --> 5.2 current 20040708 upgrade ATA_IDENTIFY no interrupt

Just upgraded from 5.2.1 p9 to 5.2-current.  Received the following error 
during boot (copied by hand, please excuse typo's):

ata0-master: FAILURE - ATA_IDENTIFY no interrupt
ata0-master: FAILURE - ATA_IDENTIFY no interrupt
Mounting root from ufs:/dev/ad0s1a
setrootbyname failed
ffs_mountroot: can't find rootvp
Root mount failed: 6

System info -

AMD Athlon 1.33 266MHZ DDR (133MHZ FSB).  1024MB ram DDR PC2100
IDE HD as Master 0, Sony DVD+/- RW as Master 1 (disabled -- see below)
NVIDIA GeForce 3 AGP
Sound Blaster LIVE
(from 5.2.1 p9 kernel dmesg)
atapci0: <VIA 8233 UDMA100 controller> port 0xff00-0xff0f at device 17.1 on 
pci0
ata0: at 0x1f0 irq 14 on atapci0
ata0: [MPSAFE]
ata1: at 0x170 irq 15 on atapci0
ata1: [MPSAFE]
ad0: 152627MB <ST3160023A> [310101/16/63] at ata0-master UDMA100


Cursory google search and scan of UPDATING found only two encounters with this 
problem, both of which used a DVD RW drive.  Thinking this might be the 
culprit, I disabled (read unplugged) my Sony DVD+/-RW drive and rebooted to 
no avail.  I attempted to boot w/ disabled ACPI, but I get the same message.

For now I have failed over to the 5.2.1 kernel which appears to work in some 
broken manner with the -current world (enough to run X).  Any suggestions for 
bootstrapping the -current kernel?

Thanks,
Justin