But I can't even boot the install image when the 16GB CF card is connected to the IDE interface. It just hangs on "Quark/OpenFirmware" if I try.
I have now got MOS installed on a 512MB card and it works fine (same CF->IDE adapter). I connected the 16GB card to a CF->USB adapter and plugged it in to the EFIKA, and HDConfig sees a device on usbscsi:0, but says no medium is inserted. So I think the card is dead
Fortunately it's a Transcend, and I think they give lifetime warranty.