diff --git a/.github/workflows/build-machines-and-homes.yml b/.github/workflows/build-machines-and-homes.yml
index 55a86db..2614cba 100644
--- a/.github/workflows/build-machines-and-homes.yml
+++ b/.github/workflows/build-machines-and-homes.yml
@@ -75,11 +75,14 @@ jobs:
         run: |
           nix run github:zhaofengli/attic push main result
 
+      - name: prepare tarball to upload
+        run: nix run github:nixos/nixpkgs#gnutar hcvf result.tar result
+
       - name: upload result
         uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.machine }}-${{ matrix.os }}
-          path: result
+          path: result.tar
           if-no-files-found: error
 
   build-homes:
@@ -141,9 +144,12 @@ jobs:
         run: |
           nix run github:zhaofengli/attic push main result
 
+      - name: prepare tarball to upload
+        run: nix run github:nixos/nixpkgs#gnutar hcvf result.tar result
+
       - name: upload result
         uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.home }}-${{ matrix.os }}
-          path: result
+          path: result.tar
           if-no-files-found: error
diff --git a/.github/workflows/build-packages.yml b/.github/workflows/build-packages.yml
index 07b76df..dbcf6c6 100644
--- a/.github/workflows/build-packages.yml
+++ b/.github/workflows/build-packages.yml
@@ -50,9 +50,12 @@ jobs:
         run: |
           nix run github:zhaofengli/attic push main result
 
+      - name: prepare tarball to upload
+        run: nix run github:nixos/nixpkgs#gnutar hcvf result.tar result
+
       - name: upload result
         uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.package }}-${{ matrix.os }}
-          path: result
+          path: result.tar
           if-no-files-found: error