diff --git a/build-constraints.yaml b/build-constraints.yaml
index 20cda6ad..8fd5cda6 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -954,6 +954,9 @@ packages:
         # https://github.com/fpco/stackage/issues/537
         - zlib < 0.6
 
+        # https://github.com/fpco/stackage/issues/549
+        - tttool < 1.4
+
 # Package flags are applied to individual packages, and override the values of
 # global-flags
 package-flags: