diff --git a/tensorflow/core/kernels/boosted_trees/resource_ops.cc b/tensorflow/core/kernels/boosted_trees/resource_ops.cc
index efb0d10c220..19a0d34326e 100644
--- a/tensorflow/core/kernels/boosted_trees/resource_ops.cc
+++ b/tensorflow/core/kernels/boosted_trees/resource_ops.cc
@@ -57,7 +57,7 @@ class BoostedTreesCreateEnsembleOp : public OpKernel {
     std::cerr << "Got a string of " << tst.size() << " characters, of type " << tst.type() << "\n";
     const char* tst_data = tst.data();
     for (int i = 0; i < tst.size(); i++) {
-      fprintf(stderr, "%02x ", tst_data[i]);
+      fprintf(stderr, "%02u ", tst_data[i]);
       if (i % 16 == 15)
         fprintf(stderr, "\n");
       else if (i % 8 == 7)
diff --git a/tensorflow/core/kernels/boosted_trees/resources.cc b/tensorflow/core/kernels/boosted_trees/resources.cc
index 6d80a177c4e..ed41677a6a2 100644
--- a/tensorflow/core/kernels/boosted_trees/resources.cc
+++ b/tensorflow/core/kernels/boosted_trees/resources.cc
@@ -40,7 +40,7 @@ bool BoostedTreesEnsembleResource::InitFromSerialized(const string& serialized,
   std::cerr << "Got a string of " << serialized.size() << " characters\n";
   const char* serialized_data = serialized.data();
   for (int i = 0; i < serialized.size(); i++) {
-    fprintf(stderr, "%02x ", serialized_data[i]);
+    fprintf(stderr, "%02u ", serialized_data[i]);
     if (i % 16 == 15)
       fprintf(stderr, "\n");
     else if (i % 8 == 7)