diff --git a/src/bin_client/test/sandbox.json b/src/bin_client/test/sandbox.json
index 87c0b22ff..86e739777 100644
--- a/src/bin_client/test/sandbox.json
+++ b/src/bin_client/test/sandbox.json
@@ -14,5 +14,6 @@
     "blocks_per_cycle" : 128,
     "blocks_per_roll_snapshot" : 32,
     "preserved_cycles" : 1,
-    "first_free_baking_slot" : 4
+    "first_free_baking_slot" : 4,
+    "proof_of_work_threshold": -1
 }
diff --git a/src/bin_client/test/test_basic.sh b/src/bin_client/test/test_basic.sh
index 0fa947ce5..6f7f3fe36 100755
--- a/src/bin_client/test/test_basic.sh
+++ b/src/bin_client/test/test_basic.sh
@@ -21,6 +21,7 @@ $client rpc call '/blocks/head/raw_context/non-existent?depth=0' | assert 'No se
 
 
 $client bake for bootstrap1 -max-priority 512
+sleep 1
 
 key1=foo
 key2=bar
diff --git a/src/proto_alpha/lib_baking/test/sandbox-vote.json b/src/proto_alpha/lib_baking/test/sandbox-vote.json
index 69fbaa1ba..41ea8eb9b 100644
--- a/src/proto_alpha/lib_baking/test/sandbox-vote.json
+++ b/src/proto_alpha/lib_baking/test/sandbox-vote.json
@@ -13,5 +13,6 @@
     "blocks_per_roll_snapshot" : 2,
     "preserved_cycles" : 1,
     "first_free_baking_slot" : 4,
-    "blocks_per_voting_period": 2
+    "blocks_per_voting_period": 2,
+    "proof_of_work_threshold": -1
 }
diff --git a/src/proto_alpha/lib_baking/test/sandbox.json b/src/proto_alpha/lib_baking/test/sandbox.json
index 81b7df766..ec8dfeae4 100644
--- a/src/proto_alpha/lib_baking/test/sandbox.json
+++ b/src/proto_alpha/lib_baking/test/sandbox.json
@@ -12,5 +12,6 @@
     "blocks_per_cycle" : 4,
     "blocks_per_roll_snapshot" : 2,
     "preserved_cycles" : 1,
-    "first_free_baking_slot" : 4
+    "first_free_baking_slot" : 4,
+    "proof_of_work_threshold": -1
 }
diff --git a/src/proto_alpha/lib_protocol/src/baking.ml b/src/proto_alpha/lib_protocol/src/baking.ml
index 4ac9d2ff3..1898f7595 100644
--- a/src/proto_alpha/lib_protocol/src/baking.ml
+++ b/src/proto_alpha/lib_protocol/src/baking.ml
@@ -249,7 +249,7 @@ let first_endorsement_slots
 let check_hash hash stamp_threshold =
   let bytes = Block_hash.to_bytes hash in
   let word = MBytes.get_int64 bytes 0 in
-  Compare.Uint64.(word < stamp_threshold)
+  Compare.Uint64.(word <= stamp_threshold)
 
 let check_header_hash header stamp_threshold =
   let hash = Block_header.hash header in