diff --git a/hw/isa/piix4.c b/hw/isa/piix4.c
index 8fc1db6dc9..0d23e11a39 100644
--- a/hw/isa/piix4.c
+++ b/hw/isa/piix4.c
@@ -116,10 +116,10 @@ static void piix4_isa_reset(DeviceState *dev)
     pci_conf[0x4c] = 0x4d;
     pci_conf[0x4e] = 0x03;
     pci_conf[0x4f] = 0x00;
-    pci_conf[0x60] = 0x0a; // PCI A -> IRQ 10
-    pci_conf[0x61] = 0x0a; // PCI B -> IRQ 10
-    pci_conf[0x62] = 0x0b; // PCI C -> IRQ 11
-    pci_conf[0x63] = 0x0b; // PCI D -> IRQ 11
+    pci_conf[0x60] = 0x80;
+    pci_conf[0x61] = 0x80;
+    pci_conf[0x62] = 0x80;
+    pci_conf[0x63] = 0x80;
     pci_conf[0x69] = 0x02;
     pci_conf[0x70] = 0x80;
     pci_conf[0x76] = 0x0c;