diff --git a/reactos/hal/halarm/generic/hal.c b/reactos/hal/halarm/generic/hal.c
index 20be7201f64..88b6f7233de 100644
--- a/reactos/hal/halarm/generic/hal.c
+++ b/reactos/hal/halarm/generic/hal.c
@@ -16,7 +16,6 @@
 #undef ExReleaseFastMutex
 #undef ExTryToAcquireFastMutex
 #undef KeAcquireSpinLock
-#undef KeGetCurrentIrql
 #undef KeLowerIrql
 #undef KeRaiseIrql
 #undef KeReleaseSpinLock
@@ -26,6 +25,7 @@
 
 /* DATA **********************************************************************/
 
+ULONG HalpCurrentTimeIncrement, HalpNextTimeIncrement, HalpNextIntervalCount;
 ULONG _KdComPortInUse = 0;
 
 ULONG HalpIrqlTable[HIGH_LEVEL + 1] =
@@ -471,9 +471,25 @@ HalpClockInterrupt(VOID)
     //
     // Clear the interrupt
     //
-    //DPRINT1("CLOCK INTERRUPT!!!\n");
-    WRITE_REGISTER_ULONG(TIMER0_INT_CLEAR, 1);    
-    //while (TRUE);
+    ASSERT(KeGetCurrentIrql() == CLOCK2_LEVEL);
+    WRITE_REGISTER_ULONG(TIMER0_INT_CLEAR, 1);
+    
+    //
+    // FIXME: Update HAL Perf counters
+    //
+    
+    //
+    // FIXME: Check if someone changed the clockrate
+    //
+    
+    //
+    // Call the kernel
+    //
+    KeUpdateSystemTime(NULL, CLOCK2_LEVEL, HalpCurrentTimeIncrement);
+    
+    //
+    // We're done
+    //
 }
 
 VOID
@@ -527,9 +543,6 @@ HalpInitializeInterrupts(VOID)
     WRITE_REGISTER_ULONG(TIMER0_CONTROL, ControlRegister.AsUlong);
 }
 
-ULONG HalpCurrentTimeIncrement, HalpNextTimeIncrement, HalpNextIntervalCount;
-
-
 /*
  * @implemented
  */
@@ -1345,6 +1358,7 @@ HalSweepIcache(VOID)
 /*
  * @implemented
  */
+#undef KeGetCurrentIrql
 KIRQL
 NTAPI
 KeGetCurrentIrql(VOID)
diff --git a/reactos/ntoskrnl/ke/arm/stubs.c b/reactos/ntoskrnl/ke/arm/stubs.c
index 977bc4d8840..83d8f537871 100644
--- a/reactos/ntoskrnl/ke/arm/stubs.c
+++ b/reactos/ntoskrnl/ke/arm/stubs.c
@@ -10,6 +10,10 @@ ULONG KeProcessorLevel;
 ULONG KeProcessorRevision;
 ULONG KeFeatureBits;
 
+
+extern LONG KiTickOffset;
+extern ULONG KeTimeAdjustment;
+
 ULONG
 KiComputeTimerTableIndex(IN LONGLONG DueTime)
 {
@@ -32,8 +36,121 @@ KeUpdateSystemTime(IN PKTRAP_FRAME TrapFrame,
                    IN KIRQL Irql,
                    IN ULONG Increment)
 {
-    UNIMPLEMENTED;
-    while (TRUE);
+    PKPRCB Prcb = KeGetPcr()->Prcb;
+    LARGE_INTEGER SystemTime, InterruptTime;
+    ULONG Hand;
+    
+    //
+    // Do nothing if this tick is being skipped
+    //
+    if (Prcb->SkipTick)
+    {
+        //
+        // Handle it next time
+        //
+        Prcb->SkipTick = FALSE;
+        return;
+    }
+    
+    //
+    // Add the increment time to the shared data
+    //
+    InterruptTime.HighPart = SharedUserData->InterruptTime.High1Time;
+    InterruptTime.LowPart = SharedUserData->InterruptTime.LowPart;
+    InterruptTime.QuadPart += Increment;
+    SharedUserData->InterruptTime.High1Time = InterruptTime.HighPart;
+    SharedUserData->InterruptTime.LowPart = InterruptTime.LowPart;
+    SharedUserData->InterruptTime.High2Time = InterruptTime.HighPart;
+    
+    //
+    // Update tick count
+    //
+    KiTickOffset -= Increment;
+    
+    //
+    // Check for incomplete tick
+    //
+    if (KiTickOffset > 0)
+    {
+        
+    }
+    else
+    {
+        //
+        // Update the system time
+        //
+        SystemTime.HighPart = SharedUserData->SystemTime.High1Time;
+        SystemTime.LowPart = SharedUserData->SystemTime.LowPart;
+        SystemTime.QuadPart += KeTimeAdjustment;
+        SharedUserData->SystemTime.High1Time = SystemTime.HighPart;
+        SharedUserData->SystemTime.LowPart = SystemTime.LowPart;
+        SharedUserData->SystemTime.High2Time = SystemTime.HighPart;
+        
+        //
+        // Update the tick count
+        //
+        SystemTime.HighPart = KeTickCount.High1Time;
+        SystemTime.LowPart = KeTickCount.LowPart;
+        SystemTime.QuadPart += 1;
+        KeTickCount.High1Time = SystemTime.HighPart;
+        KeTickCount.LowPart = SystemTime.LowPart;
+        KeTickCount.High2Time = SystemTime.HighPart;
+        
+        //
+        // Update it in the shared user data
+        //
+        SharedUserData->TickCount.High1Time = SystemTime.HighPart;
+        SharedUserData->TickCount.LowPart = SystemTime.LowPart;
+        SharedUserData->TickCount.High2Time = SystemTime.HighPart;
+    }
+    
+    //
+    // Check for timer expiration
+    //
+    Hand = KeTickCount.LowPart & (TIMER_TABLE_SIZE - 1);
+    Hand <<= 4;
+    if (KiTimerTableListHead[Hand].Time.QuadPart > InterruptTime.QuadPart)
+    {
+        //
+        // Timer has expired!
+        //
+        DPRINT1("TIMER EXPIRATION!!!\n");
+        while (TRUE);
+    }
+    
+    //
+    // Check if we should request a debugger break
+    //
+    if (KdDebuggerEnabled)
+    {
+        //
+        // Check if we should break
+        //
+        if (KdPollBreakIn()) DbgBreakPointWithStatus(DBG_STATUS_CONTROL_C);
+    }
+    
+    //
+    // Check if this was a full tick
+    //
+    if (KiTickOffset <= 0)
+    {
+        //
+        // Updare the tick offset
+        //
+        KiTickOffset += KeMaximumIncrement;
+        
+        //
+        // Update system runtime
+        //
+        KeUpdateRunTime(NULL, CLOCK2_LEVEL);
+    }
+    else
+    {
+        //
+        // Increase interrupt count and exit
+        //
+        Prcb->InterruptCount++;
+    }
 }
 
 VOID