> Code committed to HEAD, can you please test? thanks.

Great! From dmesg:

siside1 at pci0 dev 5 function 0
siside1: Silicon Integrated Systems 180/96X SATA controller (rev. 0x01)
siside1: bus-master DMA support present
siside1: primary channel configured to native-PCI mode
siside1: using irq 9 for native-PCI interrupt
atabus2 at siside1 channel 0
siside1: secondary channel configured to native-PCI mode
atabus3 at siside1 channel 1
---

The connected SATA-drive works. Many thanks!!