diff --git a/src/main.cpp b/src/main.cpp
index f67f1fd0d..4bf588369 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1343,7 +1343,8 @@ void static InvalidBlockFound(CBlockIndex *pindex, const CValidationState &state
     if (state.IsInvalid(nDoS)) {
         std::map<uint256, NodeId>::iterator it = mapBlockSource.find(pindex->GetBlockHash());
         if (it != mapBlockSource.end() && State(it->second)) {
-            CBlockReject reject = {state.GetRejectCode(), state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), pindex->GetBlockHash()};
+            assert(state.GetRejectCode() < 0x100);
+            CBlockReject reject = {(unsigned char)state.GetRejectCode(), state.GetRejectReason().substr(0, MAX_REJECT_MESSAGE_LENGTH), pindex->GetBlockHash()};
             State(it->second)->rejects.push_back(reject);
             if (nDoS > 0)
                 Misbehaving(it->second, nDoS);