diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index 11b7f6bfa1..07bab85ce5 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -1046,7 +1046,7 @@ static void fmb_update(void *opaque)
                       sizeof(pbdev->fmb.last_update))) {
         return;
     }
-    timer_mod(pbdev->fmb_timer, t + DEFAULT_MUI);
+    timer_mod(pbdev->fmb_timer, t + pbdev->pci_group->zpci_group.mui);
 }
 
 int mpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar,
@@ -1204,7 +1204,8 @@ int mpcifc_service_call(S390CPU *cpu, uint8_t r1, uint64_t fiba, uint8_t ar,
         }
         pbdev->fmb_addr = fmb_addr;
         timer_mod(pbdev->fmb_timer,
-                  qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + DEFAULT_MUI);
+                  qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
+                                    pbdev->pci_group->zpci_group.mui);
         break;
     }
     default: