diff --git a/.github/workflows/build-machines-and-homes.yml b/.github/workflows/build-machines-and-homes.yml
index b15bc22..e7b0492 100644
--- a/.github/workflows/build-machines-and-homes.yml
+++ b/.github/workflows/build-machines-and-homes.yml
@@ -140,11 +140,12 @@ jobs:
           nix run github:zhaofengli/attic login cy7 https://cache.cy7.sh "$ATTIC_TOKEN"
 
       - run: |
-          nix build -L .#homeConfigurations."${{ matrix.home }}".activationPackage
+          package=".#homeConfigurations."${{ matrix.home }}".activationPackage"
+          nix build -L "$package"
 
       - name: cache result
         run: |
-          derivation="$(nix path-info --derivation "${{ matrix.home }}")"
+          derivation="$(nix path-info --derivation "$package")"
           cache="$(nix-store --query --requisites --include-outputs "$derivation")"
           nix run github:zhaofengli/attic push main --stdin <<< "$cache"