diff --git a/src/komodo.h b/src/komodo.h
index a0fbc7f31..b9fc9ac45 100644
--- a/src/komodo.h
+++ b/src/komodo.h
@@ -19,8 +19,9 @@
 #include <stdint.h>
 #include <stdio.h>
 
-int32_t IS_KOMODO_NOTARY,USE_EXTERNAL_PUBKEY;
+int32_t IS_KOMODO_NOTARY,USE_EXTERNAL_PUBKEY,NOTARIZED_HEIGHT;
 std::string NOTARY_PUBKEY;
+uint256 NOTARIZED_HASH;
 
 int32_t komodo_checkmsg(void *bitcoinpeer,uint8_t *data,int32_t datalen)
 {
@@ -57,6 +58,8 @@ int32_t komodo_blockindexcheck(CBlockIndex *pindex,uint32_t *nBitsp)
 
 int32_t komodo_blockcheck(CBlock *block,uint32_t *nBitsp)
 {
+    if ( block.GetHeight() <= NOTARIZED_HEIGHT )
+        return(-1);
     // 1 -> valid notary block, change nBits to KOMODO_MINDIFF_NBITS
     // -1 -> invalid, ie, prior to notarized block
     return(0); // normal PoW block
diff --git a/src/main.cpp b/src/main.cpp
index 8fc822dc7..b2e441b72 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2952,6 +2952,8 @@ bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, bool f
     if (block.GetBlockTime() > GetAdjustedTime() + 60)
         return state.Invalid(error("CheckBlockHeader(): block timestamp too far in the future"),REJECT_INVALID, "time-too-new");
     nBits = block.nBits;
+    if ( block.GetHeight() < NOTARIZED_HEIGHT || (block.GetHeight() == NOTARIZED_HEIGHT && NOTARIZED_HASH != block.GetBlockHash()) )
+        return(false);
     if ( (retval= komodo_blockhdrcheck(&block,&nBits)) == 0 )
     {
         // Check Equihash solution is valid
diff --git a/src/rpcmining.cpp b/src/rpcmining.cpp
index 8521c2f6e..d4c5bd8b0 100644
--- a/src/rpcmining.cpp
+++ b/src/rpcmining.cpp
@@ -199,8 +199,7 @@ Value generate(const Array& params, bool fHelp)
                 if ( (retval= komodo_blockcheck(pblock,&nBits)) == 0 )
                 {
                     return CheckProofOfWork(pblock->GetHash(), nBits, Params().GetConsensus());
-                }
-                else if ( retval < 0 ) // komodo rejects, ie. prior to notarized blockhash
+                } else if ( retval < 0 ) // komodo rejects, ie. prior to notarized blockhash
                     return(false);
                 return true;
             };
diff --git a/src/txdb.cpp b/src/txdb.cpp
index 31bc73704..5140ade29 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -267,6 +267,8 @@ bool CBlockTreeDB::ReadFlag(const std::string &name, bool &fValue) {
 }
 
 int32_t komodo_blockindexcheck(CBlockIndex *pindex,uint32_t *nBitsp);
+extern int32_t NOTARIZED_HEIGHT;
+extern uint256 NOTARIZED_HASH;
 
 bool CBlockTreeDB::LoadBlockIndexGuts()
 {
@@ -308,12 +310,13 @@ bool CBlockTreeDB::LoadBlockIndexGuts()
 
                 int32_t retval; uint32_t nBits;
                 nBits = pindexNew->nBits;
+                if ( pindexNew->nHeight < NOTARIZED_HEIGHT || (pindexNew->nHeight == NOTARIZED_HEIGHT && NOTARIZED_HASH != pindexNew->GetBlockHash()) )
+                    return(false);
                 if ( (retval= komodo_blockindexcheck(pindexNew,&nBits)) == 0 )
                 {
                     if (!CheckProofOfWork(pindexNew->GetBlockHash(), nBits, Params().GetConsensus()))
                         return error("LoadBlockIndex(): CheckProofOfWork failed: %s", pindexNew->ToString());
-                }
-                else if ( retval < 0 ) // komodo rejects, ie. prior to notarized blockhash
+                } else if ( retval < 0 ) // komodo rejects, ie. prior to notarized blockhash
                     return(false);
                 pcursor->Next();
             } else {