diff --git a/src/com/xilinx/rapidwright/design/DesignTools.java b/src/com/xilinx/rapidwright/design/DesignTools.java
index 382c16eda..2384377ed 100644
--- a/src/com/xilinx/rapidwright/design/DesignTools.java
+++ b/src/com/xilinx/rapidwright/design/DesignTools.java
@@ -4367,13 +4367,18 @@ public static void addProhibitConstraint(Design design, List<String> belLocation
      * tied to GND or VCC) when following the Net's PIPs.
      * A source pin will be marked as being routed if it drives at least one PIP.
      * @param net Net on which pins are to be updated.
+     * @return Number of unrouted sink pins on net.
      */
-    public static void updatePinsIsRouted(Net net) {
+    public static int updatePinsIsRouted(Net net) {
+        int numUnroutedSinkPins = 0;
         for (SitePinInst spi : net.getPins()) {
             spi.setRouted(false);
+            if (!spi.isOutPin()) {
+                numUnroutedSinkPins++;
+            }
         }
         if (!net.hasPIPs()) {
-            return;
+            return numUnroutedSinkPins;
         }
 
         Map<Node, SitePinInst> node2spi = new HashMap<>();
@@ -4392,23 +4397,34 @@ public static void updatePinsIsRouted(Net net) {
         }
         while (!queue.isEmpty()) {
             NetTools.NodeTree node = queue.poll();
-            SitePinInst spi = node2spi.get(node);
+            SitePinInst spi = node2spi.remove(node);
             if (spi != null) {
                 spi.setRouted(true);
+                if (!spi.isOutPin()) {
+                    assert(numUnroutedSinkPins > 0);
+                    numUnroutedSinkPins--;
+                }
             }
             queue.addAll(node.fanouts);
         }
+        return numUnroutedSinkPins;
     }
 
     /**
      * Update the SitePinInst.isRouted() value of all sink pins in the given
      * Design. See {@link #updatePinsIsRouted(Net)}.
      * @param design Design in which pins are to be updated.
+     * @return Number of unrouted sink pins (not driven by hierarchical ports) across design.
      */
-    public static void updatePinsIsRouted(Design design) {
+    public static int updatePinsIsRouted(Design design) {
+        int totalUnroutedSinkPins = 0;
         for (Net net : design.getNets()) {
-            updatePinsIsRouted(net);
+            int numUnroutedSinkPins = updatePinsIsRouted(net);
+            if (!DesignTools.isNetDrivenByHierPort(net)) {
+                totalUnroutedSinkPins += numUnroutedSinkPins;
+            }
         }
+        return totalUnroutedSinkPins;
     }
 
     /**
diff --git a/test/src/com/xilinx/rapidwright/eco/TestECOTools.java b/test/src/com/xilinx/rapidwright/eco/TestECOTools.java
index c8cb113ad..bfd9725ea 100644
--- a/test/src/com/xilinx/rapidwright/eco/TestECOTools.java
+++ b/test/src/com/xilinx/rapidwright/eco/TestECOTools.java
@@ -187,7 +187,7 @@ public void testConnectNetSwapSinks() {
         EDIFNetlist netlist = design.getNetlist();
         Map<Net, Set<SitePinInst>> deferredRemovals = new HashMap<>();
 
-        DesignTools.updatePinsIsRouted(design);
+        Assertions.assertEquals(0, DesignTools.updatePinsIsRouted(design));
 
         // Disconnect the ILA inputs
         List<EDIFHierPortInst> disconnectPins = new ArrayList<>();
@@ -253,7 +253,7 @@ public void testConnectNetSwapSource() {
         EDIFNetlist netlist = design.getNetlist();
         Map<Net, Set<SitePinInst>> deferredRemovals = new HashMap<>();
 
-        DesignTools.updatePinsIsRouted(design);
+        Assertions.assertEquals(0, DesignTools.updatePinsIsRouted(design));
 
         // Disconnect the outputs
         List<EDIFHierPortInst> disconnectPins = new ArrayList<>();
@@ -386,7 +386,7 @@ public void testCreateCell() {
         Design design = RapidWrightDCP.loadDCP("picoblaze_ooc_X10Y235.dcp");
         EDIFNetlist netlist = design.getNetlist();
 
-        DesignTools.updatePinsIsRouted(design);
+        Assertions.assertEquals(0, DesignTools.updatePinsIsRouted(design));
 
         EDIFCell reference = netlist.getCell("kcpsm6");
         List<String> instNames = Arrays.asList("processor2", "processor3");
@@ -474,7 +474,7 @@ public void testCreateNet() {
         Design design = RapidWrightDCP.loadDCP("picoblaze_ooc_X10Y235.dcp");
         EDIFNetlist netlist = design.getNetlist();
 
-        DesignTools.updatePinsIsRouted(design);
+        Assertions.assertEquals(0, DesignTools.updatePinsIsRouted(design));
 
         List<String> netNames = Arrays.asList("processor/foo", "your_program/bar");
         ECOTools.createNet(design, netNames);
diff --git a/test/src/com/xilinx/rapidwright/interchange/TestPhysNetlistWriter.java b/test/src/com/xilinx/rapidwright/interchange/TestPhysNetlistWriter.java
index 5d358408e..2fb12f203 100644
--- a/test/src/com/xilinx/rapidwright/interchange/TestPhysNetlistWriter.java
+++ b/test/src/com/xilinx/rapidwright/interchange/TestPhysNetlistWriter.java
@@ -331,7 +331,7 @@ public void testSimulateSwappedLutPinsWithRWRoute(String path, @TempDir Path tem
             inputDesign = null;
 
             Assertions.assertTrue(LUTTools.swapLutPinsFromPIPs(outputDesign) > 0);
-            DesignTools.updatePinsIsRouted(outputDesign);
+            Assertions.assertEquals(0, DesignTools.updatePinsIsRouted(outputDesign));
             TestRWRoute.assertAllSourcesRoutedFlagSet(outputDesign);
             TestRWRoute.assertAllPinsRouted(outputDesign);
             VivadoToolsHelper.assertFullyRouted(outputDesign);
diff --git a/test/src/com/xilinx/rapidwright/rwroute/TestGlobalSignalRouting.java b/test/src/com/xilinx/rapidwright/rwroute/TestGlobalSignalRouting.java
index 379dd822d..354cdc7d0 100644
--- a/test/src/com/xilinx/rapidwright/rwroute/TestGlobalSignalRouting.java
+++ b/test/src/com/xilinx/rapidwright/rwroute/TestGlobalSignalRouting.java
@@ -339,7 +339,7 @@ public void testSymmetricClkRouting() {
                     if (node != null) used.add(node);
                 }
             }
-            DesignTools.updatePinsIsRouted(net);
+            Assertions.assertEquals(0, DesignTools.updatePinsIsRouted(net));
             for (SitePinInst spi : net.getPins()) {
                 Assertions.assertTrue(spi.isRouted());
             }