diff --git a/build-constraints.yaml b/build-constraints.yaml
index 7cc46c08..098d37c1 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -1553,8 +1553,8 @@ packages:
 
     "Gershom Bazerman <gershomb@gmail.com> @gbaz":
         - jmacro
-        - jmacro-rpc
-        - jmacro-rpc-snap
+        - jmacro-rpc < 0 # build failure with GHC 8.4 https://hub.darcs.net/gershomb/jmacro/issue/5
+        - jmacro-rpc-snap < 0 # via jmacro-rpc
         - jmacro-rpc-happstack < 0 # GHC 8.4 via happstack-server
 
         - mbox