diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c b/src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
index a7b072420ec..f6538e1349f 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
@@ -75,14 +75,14 @@ PB_STATIC_ASSERT((pb_membersize(grpc_lb_v1_LoadBalanceRequest, initial_request)
 #endif
 
 #if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
-/* If you get an error here, it means that you need to define PB_FIELD_32BIT
+/* If you get an error here, it means that you need to define PB_FIELD_16BIT
  * compile-time option. You can do that in pb.h or on compiler command line.
  * 
  * The reason you need to do this is that some of your messages contain tag
  * numbers or field sizes that are larger than what can fit in the default
  * 8 bit descriptors.
  */
-PB_STATIC_ASSERT((pb_membersize(grpc_lb_v1_LoadBalanceRequest, initial_request) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceRequest, client_stats) < 256 && pb_membersize(grpc_lb_v1_ClientStats, timestamp) < 256 && pb_membersize(grpc_lb_v1_ClientStats, calls_finished_with_drop) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceResponse, initial_response) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceResponse, server_list) < 256 && pb_membersize(grpc_lb_v1_InitialLoadBalanceResponse, client_stats_report_interval) < 256 && pb_membersize(grpc_lb_v1_ServerList, servers) < 256), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_grpc_lb_v1_LoadBalanceRequest_grpc_lb_v1_InitialLoadBalanceRequest_grpc_lb_v1_ClientStatsPerToken_grpc_lb_v1_ClientStats_grpc_lb_v1_LoadBalanceResponse_grpc_lb_v1_InitialLoadBalanceResponse_grpc_lb_v1_ServerList_grpc_lb_v1_Server)
+PB_STATIC_ASSERT((pb_membersize(grpc_lb_v1_LoadBalanceRequest, initial_request) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceRequest, client_stats) < 256 && pb_membersize(grpc_lb_v1_ClientStats, timestamp) < 256 && pb_membersize(grpc_lb_v1_ClientStats, calls_finished_with_drop) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceResponse, initial_response) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceResponse, server_list) < 256 && pb_membersize(grpc_lb_v1_InitialLoadBalanceResponse, client_stats_report_interval) < 256 && pb_membersize(grpc_lb_v1_ServerList, servers) < 256), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_grpc_lb_v1_LoadBalanceRequest_grpc_lb_v1_InitialLoadBalanceRequest_grpc_lb_v1_ClientStatsPerToken_grpc_lb_v1_ClientStats_grpc_lb_v1_LoadBalanceResponse_grpc_lb_v1_InitialLoadBalanceResponse_grpc_lb_v1_ServerList_grpc_lb_v1_Server)
 #endif
 
 
diff --git a/src/core/tsi/alts/handshaker/altscontext.pb.c b/src/core/tsi/alts/handshaker/altscontext.pb.c
index 2320edb1eff..5fb152a558e 100644
--- a/src/core/tsi/alts/handshaker/altscontext.pb.c
+++ b/src/core/tsi/alts/handshaker/altscontext.pb.c
@@ -33,14 +33,14 @@ PB_STATIC_ASSERT((pb_membersize(grpc_gcp_AltsContext, peer_rpc_versions) < 65536
 #endif
 
 #if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
-/* If you get an error here, it means that you need to define PB_FIELD_32BIT
+/* If you get an error here, it means that you need to define PB_FIELD_16BIT
  * compile-time option. You can do that in pb.h or on compiler command line.
  * 
  * The reason you need to do this is that some of your messages contain tag
  * numbers or field sizes that are larger than what can fit in the default
  * 8 bit descriptors.
  */
-PB_STATIC_ASSERT((pb_membersize(grpc_gcp_AltsContext, peer_rpc_versions) < 256), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_grpc_gcp_AltsContext)
+PB_STATIC_ASSERT((pb_membersize(grpc_gcp_AltsContext, peer_rpc_versions) < 256), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_grpc_gcp_AltsContext)
 #endif
 
 
diff --git a/src/core/tsi/alts/handshaker/handshaker.pb.c b/src/core/tsi/alts/handshaker/handshaker.pb.c
index 8eda290e123..5450b1602d4 100644
--- a/src/core/tsi/alts/handshaker/handshaker.pb.c
+++ b/src/core/tsi/alts/handshaker/handshaker.pb.c
@@ -108,14 +108,14 @@ PB_STATIC_ASSERT((pb_membersize(grpc_gcp_StartClientHandshakeReq, target_identit
 #endif
 
 #if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
-/* If you get an error here, it means that you need to define PB_FIELD_32BIT
+/* If you get an error here, it means that you need to define PB_FIELD_16BIT
  * compile-time option. You can do that in pb.h or on compiler command line.
  * 
  * The reason you need to do this is that some of your messages contain tag
  * numbers or field sizes that are larger than what can fit in the default
  * 8 bit descriptors.
  */
-PB_STATIC_ASSERT((pb_membersize(grpc_gcp_StartClientHandshakeReq, target_identities) < 256 && pb_membersize(grpc_gcp_StartClientHandshakeReq, local_identity) < 256 && pb_membersize(grpc_gcp_StartClientHandshakeReq, local_endpoint) < 256 && pb_membersize(grpc_gcp_StartClientHandshakeReq, remote_endpoint) < 256 && pb_membersize(grpc_gcp_StartClientHandshakeReq, rpc_versions) < 256 && pb_membersize(grpc_gcp_ServerHandshakeParameters, local_identities) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq, handshake_parameters[0]) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq, local_endpoint) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq, remote_endpoint) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq, rpc_versions) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq_HandshakeParametersEntry, value) < 256 && pb_membersize(grpc_gcp_HandshakerReq, client_start) < 256 && pb_membersize(grpc_gcp_HandshakerReq, server_start) < 256 && pb_membersize(grpc_gcp_HandshakerReq, next) < 256 && pb_membersize(grpc_gcp_HandshakerResult, peer_identity) < 256 && pb_membersize(grpc_gcp_HandshakerResult, local_identity) < 256 && pb_membersize(grpc_gcp_HandshakerResult, peer_rpc_versions) < 256 && pb_membersize(grpc_gcp_HandshakerResp, result) < 256 && pb_membersize(grpc_gcp_HandshakerResp, status) < 256), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_grpc_gcp_Endpoint_grpc_gcp_Identity_grpc_gcp_StartClientHandshakeReq_grpc_gcp_ServerHandshakeParameters_grpc_gcp_StartServerHandshakeReq_grpc_gcp_StartServerHandshakeReq_HandshakeParametersEntry_grpc_gcp_NextHandshakeMessageReq_grpc_gcp_HandshakerReq_grpc_gcp_HandshakerResult_grpc_gcp_HandshakerStatus_grpc_gcp_HandshakerResp)
+PB_STATIC_ASSERT((pb_membersize(grpc_gcp_StartClientHandshakeReq, target_identities) < 256 && pb_membersize(grpc_gcp_StartClientHandshakeReq, local_identity) < 256 && pb_membersize(grpc_gcp_StartClientHandshakeReq, local_endpoint) < 256 && pb_membersize(grpc_gcp_StartClientHandshakeReq, remote_endpoint) < 256 && pb_membersize(grpc_gcp_StartClientHandshakeReq, rpc_versions) < 256 && pb_membersize(grpc_gcp_ServerHandshakeParameters, local_identities) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq, handshake_parameters[0]) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq, local_endpoint) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq, remote_endpoint) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq, rpc_versions) < 256 && pb_membersize(grpc_gcp_StartServerHandshakeReq_HandshakeParametersEntry, value) < 256 && pb_membersize(grpc_gcp_HandshakerReq, client_start) < 256 && pb_membersize(grpc_gcp_HandshakerReq, server_start) < 256 && pb_membersize(grpc_gcp_HandshakerReq, next) < 256 && pb_membersize(grpc_gcp_HandshakerResult, peer_identity) < 256 && pb_membersize(grpc_gcp_HandshakerResult, local_identity) < 256 && pb_membersize(grpc_gcp_HandshakerResult, peer_rpc_versions) < 256 && pb_membersize(grpc_gcp_HandshakerResp, result) < 256 && pb_membersize(grpc_gcp_HandshakerResp, status) < 256), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_grpc_gcp_Endpoint_grpc_gcp_Identity_grpc_gcp_StartClientHandshakeReq_grpc_gcp_ServerHandshakeParameters_grpc_gcp_StartServerHandshakeReq_grpc_gcp_StartServerHandshakeReq_HandshakeParametersEntry_grpc_gcp_NextHandshakeMessageReq_grpc_gcp_HandshakerReq_grpc_gcp_HandshakerResult_grpc_gcp_HandshakerStatus_grpc_gcp_HandshakerResp)
 #endif
 
 
diff --git a/src/core/tsi/alts/handshaker/transport_security_common.pb.c b/src/core/tsi/alts/handshaker/transport_security_common.pb.c
index aac699314e7..326b1b10ab7 100644
--- a/src/core/tsi/alts/handshaker/transport_security_common.pb.c
+++ b/src/core/tsi/alts/handshaker/transport_security_common.pb.c
@@ -35,14 +35,14 @@ PB_STATIC_ASSERT((pb_membersize(grpc_gcp_RpcProtocolVersions, max_rpc_version) <
 #endif
 
 #if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
-/* If you get an error here, it means that you need to define PB_FIELD_32BIT
+/* If you get an error here, it means that you need to define PB_FIELD_16BIT
  * compile-time option. You can do that in pb.h or on compiler command line.
  * 
  * The reason you need to do this is that some of your messages contain tag
  * numbers or field sizes that are larger than what can fit in the default
  * 8 bit descriptors.
  */
-PB_STATIC_ASSERT((pb_membersize(grpc_gcp_RpcProtocolVersions, max_rpc_version) < 256 && pb_membersize(grpc_gcp_RpcProtocolVersions, min_rpc_version) < 256), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_grpc_gcp_RpcProtocolVersions_grpc_gcp_RpcProtocolVersions_Version)
+PB_STATIC_ASSERT((pb_membersize(grpc_gcp_RpcProtocolVersions, max_rpc_version) < 256 && pb_membersize(grpc_gcp_RpcProtocolVersions, min_rpc_version) < 256), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_grpc_gcp_RpcProtocolVersions_grpc_gcp_RpcProtocolVersions_Version)
 #endif