diff --git a/build-constraints.yaml b/build-constraints.yaml
index 2013458f..6183cf01 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -2080,7 +2080,7 @@ packages:
 
     "Peter Simons <simons@cryp.to> @peti":
         - cabal2nix
-        - cabal2spec
+        # - cabal2spec # build failure with ghc 8.4 https://github.com/peti/cabal2spec/issues/1
         - distribution-nixpkgs
         - funcmp
         - hackage-db
@@ -3272,6 +3272,7 @@ packages:
         - PSQueue < 0 # build failure with GHC 8.4 (nowhere to report, it's ancient just let it die)
         - Rasterific < 0 # build failure with GHC 8.4 https://github.com/Twinside/Rasterific/issues/38
         - b9 < 0 # build failure with GHC 8.4 https://github.com/sheyll/b9-vm-image-builder/issues/4
+        - cabal2spec < 0 # build failure with GHC 8.4 https://github.com/peti/cabal2spec/issues/1
         - cabal-rpm < 0 # build failure with GHC 8.4 https://github.com/juhp/cabal-rpm/issues/55
         - dom-parser < 0 # build failure with GHC 8.4 https://github.com/typeable/dom-parser/issues/10
         - enummapset < 0 # build failure with GHC 8.4 https://github.com/michalt/enummapset/issues/11