diff --git a/libethereum/BlockChain.cpp b/libethereum/BlockChain.cpp
index a76435ada..352739626 100644
--- a/libethereum/BlockChain.cpp
+++ b/libethereum/BlockChain.cpp
@@ -398,9 +398,11 @@ ImportRoute BlockChain::import(bytes const& _block, OverlayDB const& _db, Import
 	if (!pd)
 	{
 		auto pdata = pd.rlp();
-		cwarn << "Odd: details is returning false despite block known:" << RLP(pdata);
+		clog(BlockChainDebug) << "Details is returning false despite block known:" << RLP(pdata);
 		auto parentBlock = block(bi.parentHash);
-		cwarn << "Block:" << RLP(parentBlock);
+		clog(BlockChainDebug) << "Block:" << RLP(parentBlock);
+		clog(BlockChainDebug) << "DATABASE CORRUPTION: CRITICAL FAILURE";
+		exit(-1);
 	}
 
 	// Check it's not crazy
@@ -620,6 +622,14 @@ ImportRoute BlockChain::import(bytes const& _block, OverlayDB const& _db, Import
 	cnote << "checkBest:" << checkBest;
 #endif
 
+	if (isKnown(bi.hash()) && !details(bi.hash()))
+	{
+		clog(BlockChainDebug) << "Known block just inserted has no details.";
+		clog(BlockChainDebug) << "Block:" << bi;
+		clog(BlockChainDebug) << "DATABASE CORRUPTION: CRITICAL FAILURE";
+		exit(-1);
+	}
+
 	h256s fresh;
 	h256s dead;
 	bool isOld = true;
diff --git a/libethereum/BlockChain.h b/libethereum/BlockChain.h
index 0529e305e..70a9f93db 100644
--- a/libethereum/BlockChain.h
+++ b/libethereum/BlockChain.h
@@ -59,6 +59,7 @@ struct FutureTime: virtual Exception {};
 struct BlockChainChat: public LogChannel { static const char* name() { return "-B-"; } static const int verbosity = 7; };
 struct BlockChainNote: public LogChannel { static const char* name() { return "=B="; } static const int verbosity = 4; };
 struct BlockChainWarn: public LogChannel { static const char* name() { return "=B="; } static const int verbosity = 1; };
+struct BlockChainDebug: public LogChannel { static const char* name() { return "#B#"; } static const int verbosity = 0; };
 
 // TODO: Move all this Genesis stuff into Genesis.h/.cpp
 std::map<Address, Account> const& genesisState();
diff --git a/libethereum/EthereumPeer.cpp b/libethereum/EthereumPeer.cpp
index 83fe22a71..9fbbdd61e 100644
--- a/libethereum/EthereumPeer.cpp
+++ b/libethereum/EthereumPeer.cpp
@@ -405,6 +405,13 @@ bool EthereumPeer::interpret(unsigned _id, RLP const& _r)
 	{
 		unsigned count = _r.itemCount();
 		clog(NetMessageSummary) << "GetBlocks (" << dec << count << "entries)";
+
+		if (!count)
+		{
+			clog(NetImpolite) << "Zero-entry GetBlocks: Not replying.";
+			addRating(-10);
+			break;
+		}
 		// return the requested blocks.
 		bytes rlp;
 		unsigned n = 0;
diff --git a/libp2p/Common.h b/libp2p/Common.h
index 9ad5bb206..691ef7fb3 100644
--- a/libp2p/Common.h
+++ b/libp2p/Common.h
@@ -77,6 +77,7 @@ struct InvalidHostIPAddress: virtual dev::Exception {};
 
 struct NetWarn: public LogChannel { static const char* name() { return "!N!"; } static const int verbosity = 0; };
 struct NetNote: public LogChannel { static const char* name() { return "*N*"; } static const int verbosity = 1; };
+struct NetImpolite: public LogChannel { static const char* name() { return "#!*"; } static const int verbosity = 1; };
 struct NetMessageSummary: public LogChannel { static const char* name() { return "-N-"; } static const int verbosity = 2; };
 struct NetConnect: public LogChannel { static const char* name() { return "+N+"; } static const int verbosity = 10; };
 struct NetMessageDetail: public LogChannel { static const char* name() { return "=N="; } static const int verbosity = 5; };