[ci] Speed up by fixing the nix instalation in ubuntu containers

Author: engdoreis

.github/workflows/ci.yml

@@ -81,63 +81,51 @@ jobs:
         run: |
           ctest --test-dir build/sw -R sim_verilator
 
-  fpga-build:
-    runs-on: ["ubuntu-22.04-bitstream"]
-    needs: verilator-test 
-    outputs:
-      bitstream-hash: ${{ steps.hash-bitstream.outputs.hash }}
+  # fpga-build:
+  #   runs-on: ["ubuntu-22.04-bitstream"]
+  #   needs: verilator-test 
+  #   outputs:
+  #     bitstream-hash: ${{ steps.hash-bitstream.outputs.hash }}
+  #   steps:
+  #     - uses: actions/checkout@v5
+  #
+  #     - name: Install Nix
+  #       run: |
+  #         sudo chown -R $(whoami) /nix
+  #
+  #     - name: Hash Bitstream
+  #       id: hash-bitstream
+  #       run: |
+  #         echo "hash=$(nix run .#bitstream-hash)" >> $GITHUB_OUTPUT
+  #
+  #     - uses: actions/cache@v5
+  #       id: cache
+  #       with:
+  #         path: build/lowrisc_mocha_chip_mocha_genesys2_0/synth-vivado/lowrisc_mocha_chip_mocha_genesys2_0.bit
+  #         key: ${{ steps.hash-bitstream.outputs.hash }}
+  #         lookup-only: true
+  #
+  #     - name: Build bitstream
+  #       if: steps.cache.outputs.cache-hit != 'true'
+  #       run: |
+  #         module load xilinx/vivado
+  #         nix run .#bitstream-build
+
+  fpga-test:
+    runs-on: ["self-hosted", "ubuntu-22.04-fpga", "genesys2"]
+    # needs: fpga-build 
     steps:
       - uses: actions/checkout@v5
 
-       # This step is a workaround and should be removed when the container is fixed.
-      - name: Uninstall Nix
-        run: |
-          sudo rm -rf /etc/nix /etc/profile.d/nix.sh /etc/tmpfiles.d/nix-daemon.conf \
-          /nix ~root/.nix-channels ~root/.nix-defexpr ~root/.nix-profile ~root/.cache/nix
-
       - name: Install Nix
-        uses: cachix/install-nix-action@v27
-        with:
-          extra_nix_config: |
-            substituters = https://nix-cache.lowrisc.org/public/ https://cache.nixos.org/
-            trusted-public-keys = nix-cache.lowrisc.org-public-1:O6JLD0yXzaJDPiQW1meVu32JIDViuaPtGDfjlOopU7o= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
+        run: |
+          sudo chown -R $(whoami) /nix
 
       - name: Hash Bitstream
         id: hash-bitstream
         run: |
           echo "hash=$(nix run .#bitstream-hash)" >> $GITHUB_OUTPUT
 
-      - uses: actions/cache@v5
-        id: cache
-        with:
-          path: build/lowrisc_mocha_chip_mocha_genesys2_0/synth-vivado/lowrisc_mocha_chip_mocha_genesys2_0.bit
-          key: ${{ steps.hash-bitstream.outputs.hash }}
-          lookup-only: true
-
-      - name: Build bitstream
-        if: steps.cache.outputs.cache-hit != 'true'
-        run: |
-          module load xilinx/vivado
-          nix run .#bitstream-build
-
-  fpga-test:
-    runs-on: ["self-hosted", "ubuntu-22.04-fpga", "genesys2"]
-    needs: fpga-build 
-    steps:
-      - uses: actions/checkout@v5
-
-       # This step is a workaround and should be removed when the container is fixed.
-      - name: Uninstall Nix
-        run: |
-          sudo rm -rf /etc/nix /etc/profile.d/nix.sh /etc/tmpfiles.d/nix-daemon.conf \
-          /nix ~root/.nix-channels ~root/.nix-defexpr ~root/.nix-profile ~root/.cache/nix
-
-      - name: Install Nix
-        uses: cachix/install-nix-action@v27
-        with:
-          extra_nix_config: |
-            substituters = https://nix-cache.lowrisc.org/public/ https://cache.nixos.org/
-            trusted-public-keys = nix-cache.lowrisc.org-public-1:O6JLD0yXzaJDPiQW1meVu32JIDViuaPtGDfjlOopU7o= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
 
       - uses: actions/cache@v5
         with: