diff --git a/src/add-ons/kernel/busses/usb/ohci.cpp b/src/add-ons/kernel/busses/usb/ohci.cpp
index 5540eabaeb..639bed3592 100644
--- a/src/add-ons/kernel/busses/usb/ohci.cpp
+++ b/src/add-ons/kernel/busses/usb/ohci.cpp
@@ -193,7 +193,8 @@ OHCI::OHCI( pci_info *info , Stack *stack )
 	int i;
 	hcd_soft_endpoint *sed, *psed;
 	dprintf( "OHCI: constructing new BusManager\n" );
-	m_opreg_base = OHCI::pci_module->read_pci_config(m_pcii->bus, m_pcii->device, m_pcii->function, 0x20 , 4 ) ^ 1;
+	m_opreg_base = OHCI::pci_module->read_pci_config(m_pcii->bus, m_pcii->device, m_pcii->function, 0x20, 4);
+	m_opreg_base &= ~PCI_address_io_mask;
 	TRACE( "OHCI: iospace offset: %lx\n" , m_opreg_base );
 	m_roothub_base = 255; //Invalidate the Root Hub address
 	{
diff --git a/src/add-ons/kernel/busses/usb/uhci.cpp b/src/add-ons/kernel/busses/usb/uhci.cpp
index 0a0e4b1798..ec3e5e94a6 100644
--- a/src/add-ons/kernel/busses/usb/uhci.cpp
+++ b/src/add-ons/kernel/busses/usb/uhci.cpp
@@ -153,7 +153,8 @@ UHCI::UHCI( pci_info *info , Stack *stack )
 	dprintf( "UHCI: constructing new BusManager\n" );
 	m_pcii = info;
 	m_stack = stack;
-	m_reg_base = UHCI::pci_module->read_pci_config(m_pcii->bus, m_pcii->device, m_pcii->function, PCI_memory_base , 4 ) & PCI_address_io_mask ;
+	m_reg_base = UHCI::pci_module->read_pci_config(m_pcii->bus, m_pcii->device, m_pcii->function, PCI_memory_base, 4);
+	m_reg_base &= ~PCI_address_io_mask;
 	TRACE( "USB UHCI: iospace offset: %lx\n" , m_reg_base );
 	m_rh_address = 255; //Invalidate the RH address
 	{