diff --git a/default.nix b/default.nix
index d42df5ab..c2f023e0 100644
--- a/default.nix
+++ b/default.nix
@@ -68,8 +68,8 @@ let
         '';
       };
       nvramDataSize = appDir: pkgs.runCommand "nvram-data-size" {} ''
-        envram_data="0x$(cat  | grep _envram_data '${appDir + /debug/app.map}' | cut -f1 -d' ')"
-        nvram_data="0x$(grep _nvram_data '${appDir + /debug/app.map}' | cut -f1 -d' ')"
+        envram_data="$(grep _envram_data '${appDir + /debug/app.map}' | tr -s ' ' | cut -f2 -d' ')"
+        nvram_data="$(grep _nvram_data '${appDir + /debug/app.map}' | tr -s ' ' | cut -f2 -d' ')"
         echo "$(($envram_data - $nvram_data))" > "$out"
       '';
       mkRelease = short_name: name: appDir: pkgs.runCommand "${short_name}-nano-${bolos.name}-release-dir" {} ''