diff --git a/hbs2-core/lib/HBS2/Net/Proto/Definition.hs b/hbs2-core/lib/HBS2/Net/Proto/Definition.hs
index 2462b1b6..6bfe147e 100644
--- a/hbs2-core/lib/HBS2/Net/Proto/Definition.hs
+++ b/hbs2-core/lib/HBS2/Net/Proto/Definition.hs
@@ -52,7 +52,10 @@ instance HasProtocol UDP (BlockInfo UDP) where
   type instance Encoded UDP = ByteString
   decode = either (const Nothing) Just . deserialiseOrFail
   encode = serialise
-  requestMinPeriod = Just 5
+
+  -- FIXME: requestMinPeriod-breaks-fast-block-download
+  --
+  requestMinPeriod = Nothing
 
 instance HasProtocol UDP (BlockChunks UDP) where
   type instance ProtocolId (BlockChunks UDP) = 2