diff --git a/flake.nix b/flake.nix
index 18a72387e5..a4ce518f1c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -149,7 +149,7 @@
               # to discover space leaks Once #4698 and #4699 are done we can
               # further constrain the heap size.
               preCheck = lib.mkForce ''
-              export GHCRTS=-M200M
+              export GHCRTS=-M250M
               '';
 
               # pkgs are instantiated for the host platform