diff --git a/src/dev/arm/RealView.py b/src/dev/arm/RealView.py
index 30e498ce1..8b9b4c20d 100644
--- a/src/dev/arm/RealView.py
+++ b/src/dev/arm/RealView.py
@@ -231,7 +231,7 @@ class CpuLocalTimer(BasicPioDevice):
 class GenericTimer(SimObject):
     type = 'GenericTimer'
     cxx_header = "dev/arm/generic_timer.hh"
-    system = Param.System(Parent.any, "system")
+    system = Param.ArmSystem(Parent.any, "system")
     gic = Param.BaseGic(Parent.any, "GIC to use for interrupting")
     # @todo: for now only two timers per CPU is supported, which is the
     # normal behaviour when security extensions are disabled.
diff --git a/src/dev/arm/generic_timer.cc b/src/dev/arm/generic_timer.cc
index 173855b88..1b8d917e9 100644
--- a/src/dev/arm/generic_timer.cc
+++ b/src/dev/arm/generic_timer.cc
@@ -234,7 +234,8 @@ GenericTimer::GenericTimer(GenericTimerParams *p)
       irqPhys(p->int_phys),
       irqVirt(p->int_virt)
 {
-    dynamic_cast<ArmSystem &>(*p->system).setGenericTimer(this);
+    fatal_if(!p->system, "No system specified, can't instantiate timer.\n");
+    p->system->setGenericTimer(this);
 }
 
 void