diff --git a/.github/actions/debian-based-image-build-setup/action.yml b/.github/actions/debian-based-image-build-setup/action.yml
index cd985140697..5956f8c2a0d 100644
--- a/.github/actions/debian-based-image-build-setup/action.yml
+++ b/.github/actions/debian-based-image-build-setup/action.yml
@@ -16,7 +16,15 @@ runs:
     run: sudo apt-get -qq update || ( apt-get -qq update && apt-get -qq install --no-install-recommends -y sudo ; )
     shell: bash
   - name: Install tools
-    run: sudo apt-get install -qq --no-install-recommends -y git-restore-mtime zstd tar
+    run: sudo apt-get install -qq --no-install-recommends -y zstd tar curl python3
+    shell: bash
+  - name: Install git-restore-mtime
+    # The GitHub Actions runner ships a Git version newer than the distro's,
+    # which can break the distro's git-restore-mtime package. Install a
+    # newer version directly from upstream.
+    run: |
+      sudo curl -fsSL -o /usr/local/bin/git-restore-mtime https://raw.githubusercontent.com/MestreLion/git-tools/v2025.08/git-restore-mtime
+      sudo chmod +x /usr/local/bin/git-restore-mtime
     shell: bash
   - name: Add 32-bit Arch
     run: sudo dpkg --add-architecture i386 && sudo apt-get update
diff --git a/.github/actions/setup-build-and-test-w-make-impl/action.yml b/.github/actions/setup-build-and-test-w-make-impl/action.yml
index faae00bc1f2..367d498b067 100644
--- a/.github/actions/setup-build-and-test-w-make-impl/action.yml
+++ b/.github/actions/setup-build-and-test-w-make-impl/action.yml
@@ -29,11 +29,11 @@ runs:
   - name: Cache build
     uses: actions/cache@v4
     with:
-      key: v2-build-cache-${{ inputs.job_name }}.${{ inputs.setup_toolchain_extra }}.${{ inputs.configure_extra }}-${{ runner.arch }}-${{ github.ref_name }}-${{ github.sha }}
+      key: v3-build-cache-${{ inputs.job_name }}.${{ inputs.setup_toolchain_extra }}.${{ inputs.configure_extra }}-${{ runner.arch }}-${{ github.ref_name }}-${{ github.sha }}
       path: build.tar.zstd
       restore-keys: |
-        v2-build-cache-${{ inputs.job_name }}.${{ inputs.setup_toolchain_extra }}.${{ inputs.configure_extra }}-${{ runner.arch }}-${{ github.ref_name }}-
-        v2-build-cache-${{ inputs.job_name }}.${{ inputs.setup_toolchain_extra }}.${{ inputs.configure_extra }}-${{ runner.arch }}-${{ github.base_ref }}-
+        v3-build-cache-${{ inputs.job_name }}.${{ inputs.setup_toolchain_extra }}.${{ inputs.configure_extra }}-${{ runner.arch }}-${{ github.ref_name }}-
+        v3-build-cache-${{ inputs.job_name }}.${{ inputs.setup_toolchain_extra }}.${{ inputs.configure_extra }}-${{ runner.arch }}-${{ github.base_ref }}-
   # Would be nice to use the cache action output, but we want to unpack even on
   # restore_keys hit.
   - name: Unpack build cache