pci_read_config_dword(dev, PCI_ROM_ADDRESS, &val);
val &= ~PCI_ROM_ADDRESS_ENABLE;
pci_write_config_dword(dev, PCI_ROM_ADDRESS, val);
pci_read_config_dword(dev, PCI_ROM_ADDRESS, &val);
val &= ~PCI_ROM_ADDRESS_ENABLE;
pci_write_config_dword(dev, PCI_ROM_ADDRESS, val);