diff --git a/machines/machineyosemite.cpp b/machines/machineyosemite.cpp
index 56d34eb..bd68633 100644
--- a/machines/machineyosemite.cpp
+++ b/machines/machineyosemite.cpp
@@ -59,6 +59,10 @@ int initialize_yosemite(std::string& id)
     grackle_obj->pci_register_device(DEV_FUN(13,0),
         dynamic_cast<PCIBase*>(gMachineObj->get_comp_by_name("Dec21154")));
 
+    // register CMD646U2 PCI Ultra ATA Controller
+    sec_bridge->pci_register_device(DEV_FUN(1,0),
+        dynamic_cast<PCIDevice*>(gMachineObj->get_comp_by_name("CmdAta")));
+
     sec_bridge->pci_register_device(DEV_FUN(5,0),
         dynamic_cast<PCIDevice*>(gMachineObj->get_comp_by_name("Heathrow")));
 
@@ -126,7 +130,7 @@ static const PropMap yosemite_settings = {
 };
 
 static vector<string> yosemite_devices = {
-    "Grackle", "Dec21154", "BurgundySnd", "Heathrow", "AtapiCdrom"
+    "Grackle", "Dec21154", "CmdAta", "BurgundySnd", "Heathrow", "AtapiCdrom"
 };
 
 static const MachineDescription yosemite_descriptor = {