diff --git a/.github/workflows/test-per-system.yml b/.github/workflows/test-per-system.yml
index 8f33291..f3550f9 100644
--- a/.github/workflows/test-per-system.yml
+++ b/.github/workflows/test-per-system.yml
@@ -24,7 +24,7 @@ jobs:
   simple-build:
     runs-on: ${{ inputs.runs-on }}
     steps:
-    - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
     - name: Install Nix
       uses: ./
       with:
@@ -40,7 +40,7 @@ jobs:
   custom-nix-path:
     runs-on: ${{ inputs.runs-on }}
     steps:
-    - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
     - name: Install Nix
       uses: ./
       with:
@@ -51,7 +51,7 @@ jobs:
   extra-nix-config:
     runs-on: ${{ inputs.runs-on }}
     steps:
-    - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
     - name: Install Nix
       uses: ./
       with:
@@ -64,7 +64,7 @@ jobs:
   flakes:
     runs-on: ${{ inputs.runs-on }}
     steps:
-    - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
     - name: Install Nix
       uses: ./
     - run: nix flake show github:NixOS/nixpkgs
@@ -72,7 +72,7 @@ jobs:
   latest-installer:
     runs-on: ${{ inputs.runs-on }}
     steps:
-    - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
     - name: Run NAR server
       run: |
         curl --location https://github.com/cachix/nar-toolbox/releases/download/v0.1.0/nar-toolbox-${{ inputs.system }} -O
@@ -89,7 +89,7 @@ jobs:
   oldest-supported-installer:
     runs-on: ${{ inputs.runs-on }}
     steps:
-    - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
     - name: Install Nix
       uses: ./
       with:
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index e94a7e0..e974b11 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -54,7 +54,7 @@ jobs:
   act-support:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+    - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
     - run: curl https://raw.githubusercontent.com/nektos/act/master/install.sh | sudo bash
     - run: docker pull ghcr.io/catthehacker/ubuntu:js-24.04
     - run: |
diff --git a/.github/workflows/update-nix.yml b/.github/workflows/update-nix.yml
index 8884247..de5fb8c 100644
--- a/.github/workflows/update-nix.yml
+++ b/.github/workflows/update-nix.yml
@@ -8,7 +8,7 @@ jobs:
   update-nix-releases:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@v6
       - name: Update nix releases
         env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/install-nix.sh b/install-nix.sh
index 0386886..0410471 100755
--- a/install-nix.sh
+++ b/install-nix.sh
@@ -102,7 +102,7 @@ echo "installer options: ${installer_options[*]}"
 
 # There is --retry-on-errors, but only newer curl versions support that
 curl_retries=5
-nix_version=2.34.7
+nix_version=2.34.5
 while ! curl -sS -o "$workdir/install" -v --fail -L "${INPUT_INSTALL_URL:-https://releases.nixos.org/nix/nix-${nix_version}/install}"; do
   sleep 1
   ((curl_retries--))