diff --git a/openfpga/src/repack/check_lb_rr_graph.cpp b/openfpga/src/repack/check_lb_rr_graph.cpp
index 64b286b62..1f8a7e9c8 100644
--- a/openfpga/src/repack/check_lb_rr_graph.cpp
+++ b/openfpga/src/repack/check_lb_rr_graph.cpp
@@ -76,6 +76,10 @@ static bool check_lb_rr_graph_dangling_nodes(const LbRRGraph& lb_rr_graph) {
    * If so, this is a dangling nodes and report 
    */
   for (auto node : lb_rr_graph.nodes()) {
+    /* Bypass 0-capacity node; They can be dangling */
+    if (0 == lb_rr_graph.node_capacity(node)) {
+      continue;
+    }
     if ((0 == lb_rr_graph.node_in_edges(node).size())
       && (0 == lb_rr_graph.node_out_edges(node).size())) {
       /* Print a warning! */
@@ -105,6 +109,10 @@ static bool check_lb_rr_graph_source_nodes(const LbRRGraph& lb_rr_graph) {
     if (LB_SOURCE != lb_rr_graph.node_type(node)) {
       continue;
     }
+    /* Bypass 0-capacity node; They can be dangling */
+    if (0 == lb_rr_graph.node_capacity(node)) {
+      continue;
+    }
     if ((0 != lb_rr_graph.node_in_edges(node).size())
       || (0 == lb_rr_graph.node_out_edges(node).size())) {
       /* Print a warning! */
@@ -134,6 +142,10 @@ static bool check_lb_rr_graph_sink_nodes(const LbRRGraph& lb_rr_graph) {
     if (LB_SINK != lb_rr_graph.node_type(node)) {
       continue;
     }
+    /* Bypass 0-capacity node; They can be dangling */
+    if (0 == lb_rr_graph.node_capacity(node)) {
+      continue;
+    }
     if ((0 == lb_rr_graph.node_in_edges(node).size())
       || (0 != lb_rr_graph.node_out_edges(node).size())) {
       /* Print a warning! */
@@ -184,16 +196,6 @@ bool check_lb_rr_graph(const LbRRGraph& lb_rr_graph) {
     num_err++;
   }
 
-  if (false == check_lb_rr_graph_source_nodes(lb_rr_graph)) {
-    VTR_LOG_WARN("Fail in checking source nodes!\n");
-    num_err++;
-  }
-
-  if (false == check_lb_rr_graph_sink_nodes(lb_rr_graph)) {
-    VTR_LOG_WARN("Fail in checking sink nodes!\n");
-    num_err++;
-  }
-
   /* Error out if there is any fatal errors found */
   if (0 < num_err) {
     VTR_LOG_WARN("Checked Logical tile Routing Resource graph with %d errors !\n",
diff --git a/openfpga/src/repack/lb_rr_graph_utils.cpp b/openfpga/src/repack/lb_rr_graph_utils.cpp
index a2e1df63a..001a2af17 100644
--- a/openfpga/src/repack/lb_rr_graph_utils.cpp
+++ b/openfpga/src/repack/lb_rr_graph_utils.cpp
@@ -63,7 +63,10 @@ void print_lb_rr_node(const LbRRGraph& lb_rr_graph,
     VTR_LOG("Node id: %d\n", size_t(node));
     VTR_LOG("Node type: %s\n", lb_rr_type_str[lb_rr_graph.node_type(node)]);
     VTR_LOG("Node capacity: %d\n", lb_rr_graph.node_capacity(node));
-    VTR_LOG("Node pb_graph_pin: %s\n", lb_rr_graph.node_pb_graph_pin(node)->to_string().c_str());
+    /* Some node, e.g., SOURCE, SINK  may not have pb_graph_pin, skip outputing in this case */
+    if (nullptr != lb_rr_graph.node_pb_graph_pin(node)) {
+      VTR_LOG("Node pb_graph_pin: %s\n", lb_rr_graph.node_pb_graph_pin(node)->to_string().c_str());
+    }
     VTR_LOG("Node intrinsic_cost: %f\n", lb_rr_graph.node_intrinsic_cost(node));
     VTR_LOG("Node num in_edges: %ld\n", lb_rr_graph.node_in_edges(node).size());
     VTR_LOG("Node num out_edges: %ld\n", lb_rr_graph.node_out_edges(node).size());