diff --git a/ethcore/res/ethereum/foundation.json b/ethcore/res/ethereum/foundation.json
index 7f9f68824..fbc91a3da 100644
--- a/ethcore/res/ethereum/foundation.json
+++ b/ethcore/res/ethereum/foundation.json
@@ -136,7 +136,8 @@
 				"eip100bTransition": "0x42ae50",
 				"difficultyBombDelays": {
 					"0x42ae50": "0x2dc6c0",
-					"0x6f1580": "0x1e8480"
+					"0x6f1580": "0x1e8480",
+					"0x8c6180": "0x3d0900"
 				}
 			}
 		}
diff --git a/ethcore/res/ethereum/ropsten.json b/ethcore/res/ethereum/ropsten.json
index cd5352414..477512ec9 100644
--- a/ethcore/res/ethereum/ropsten.json
+++ b/ethcore/res/ethereum/ropsten.json
@@ -16,7 +16,8 @@
 				"eip100bTransition": "0x19f0a0",
 				"difficultyBombDelays": {
 					"0x19f0a0": "0x2dc6c0",
-					"0x408b70": "0x1e8480"
+					"0x408b70": "0x1e8480",
+					"0x6c993d": "0x3d0900"
 				}
 			}
 		}