diff --git a/src/core/surface/validate_metadata.c b/src/core/surface/validate_metadata.c
index df2e80b4b78cdf35a401fd475bfd6f10ad182a77..bf4126867fd7e68b4381f6a9d37d89ef075ba9b8 100644
--- a/src/core/surface/validate_metadata.c
+++ b/src/core/surface/validate_metadata.c
@@ -50,7 +50,7 @@ static int conforms_to(const char *s, size_t len, const uint8_t *legal_bits) {
 
 int grpc_header_key_is_legal(const char *key, size_t length) {
   static const uint8_t legal_header_bits[256 / 8] = {
-      0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0xff, 0x03, 0x00, 0x00, 0x00,
+      0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0xff, 0x03, 0x00, 0x00, 0x00,
       0x80, 0xfe, 0xff, 0xff, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
   if (length == 0) {
diff --git a/test/cpp/end2end/async_end2end_test.cc b/test/cpp/end2end/async_end2end_test.cc
index 252bda3798803de66977ba288ff0637c22dea459..a194c615cdfd1965623371d1627abc8c4d5af52f 100644
--- a/test/cpp/end2end/async_end2end_test.cc
+++ b/test/cpp/end2end/async_end2end_test.cc
@@ -479,8 +479,10 @@ TEST_P(AsyncEnd2endTest, ClientInitialMetadataRpc) {
   send_request.set_message("Hello");
   std::pair<grpc::string, grpc::string> meta1("key1", "val1");
   std::pair<grpc::string, grpc::string> meta2("key2", "val2");
+  std::pair<grpc::string, grpc::string> meta3("g.r.d-bin", "xyz");
   cli_ctx.AddMetadata(meta1.first, meta1.second);
   cli_ctx.AddMetadata(meta2.first, meta2.second);
+  cli_ctx.AddMetadata(meta3.first, meta3.second);
 
   std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
       stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));
@@ -494,6 +496,8 @@ TEST_P(AsyncEnd2endTest, ClientInitialMetadataRpc) {
             ToString(client_initial_metadata.find(meta1.first)->second));
   EXPECT_EQ(meta2.second,
             ToString(client_initial_metadata.find(meta2.first)->second));
+  EXPECT_EQ(meta3.second,
+            ToString(client_initial_metadata.find(meta3.first)->second));
   EXPECT_GE(client_initial_metadata.size(), static_cast<size_t>(2));
 
   send_response.set_message(recv_request.message());
diff --git a/tools/codegen/core/gen_legal_metadata_characters.c b/tools/codegen/core/gen_legal_metadata_characters.c
index 3c9e1c7619b1469cdc6680bd4e11d4aeb55148bb..6ac32656cbb2b28d2b68c38c6e56c181307319a3 100644
--- a/tools/codegen/core/gen_legal_metadata_characters.c
+++ b/tools/codegen/core/gen_legal_metadata_characters.c
@@ -52,7 +52,7 @@ static void legal(int x) {
 static void dump(void) {
   int i;
 
-  printf("static const gpr_uint8 legal_header_bits[256/8] = ");
+  printf("static const uint8_t legal_header_bits[256/8] = ");
   for (i = 0; i < 256 / 8; i++)
     printf("%c 0x%02x", i ? ',' : '{', legal_bits[i]);
   printf(" };\n");