diff --git a/pkgs/by-name/si/signal-desktop-bin/update.sh b/pkgs/by-name/si/signal-desktop-bin/update.sh
index 3205a41a1abf..10b73d331c91 100755
--- a/pkgs/by-name/si/signal-desktop-bin/update.sh
+++ b/pkgs/by-name/si/signal-desktop-bin/update.sh
@@ -17,6 +17,8 @@ latestBuildAarch64=$(jq '.id' <<< $latestBuildInfoAarch64)
 latestVersionAarch64=$(jq -r '.source_package.version' <<< $latestBuildInfoAarch64)
 latestPrettyVersionAarch64="${latestVersionAarch64%-*}"
 
+darwinHash="$(nix hash convert --hash-algo sha256 --to sri "$(nix-prefetch-url "https://updates.signal.org/desktop/signal-desktop-mac-universal-${latestVersion}.dmg")")"
+
 echo "Updating signal-desktop for x86_64-linux"
 update-source-version signal-desktop-bin "$latestVersion" \
   --system=x86_64-linux \
@@ -29,6 +31,5 @@ update-source-version signal-desktop-bin "$latestPrettyVersionAarch64" "" \
   --file="$SCRIPT_DIR/signal-desktop-aarch64.nix"
 
 echo "Updating signal-desktop for darwin"
-update-source-version signal-desktop-bin "$latestVersion" \
-  --system=aarch64-darwin \
-  --file="$SCRIPT_DIR/signal-desktop-darwin.nix"
+sed -i "s|version = \".*\";|version = \"${latestVersion}\";|" "$SCRIPT_DIR/signal-desktop-darwin.nix"
+sed -i "s|hash = \"sha256-[^\"]*\";|hash = \"${darwinHash}\";|" "$SCRIPT_DIR/signal-desktop-darwin.nix"