You should be right.
When I was testing that on Broadcom BLAST ref board: STAT and IDE doesn't work.
But on another MB (serverworks HT1000 based), IDE is working.
Maybe some magic bit in pci conf space need to set by option rom...
You could compare the pci conf dump between system bios and LinuxBIOS...
BTW, Can drop your funny signature in LinuxBIOS?
YH