diff --git a/.bcr/core/presubmit.yml b/.bcr/core/presubmit.yml
index 14fcfd0f2..2171bfffa 100644
--- a/.bcr/core/presubmit.yml
+++ b/.bcr/core/presubmit.yml
@@ -6,10 +6,11 @@ bcr_test_module:
     run_tests:
       name: "Run test module"
       platform: ${{ platform }}
+      environment:
+        # The Nix installer updates ~/.profile to set PATH. However, the Bazel
+        # CI setup seems to disregard ~/.profile. So we set PATH manually here.
+        PATH: /var/lib/buildkite-agent/.nix-profile/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
       shell_commands:
-        - apt update
-        - apt install --yes nix-setup-systemd
-        - nix-channel --add https://nixos.org/channels/nixpkgs-unstable nixpkgs
-        - nix-channel --update
+        - curl -L https://nixos.org/nix/install | sh -s -- --no-daemon
       test_targets:
         - "//..."
diff --git a/.bcr/core/source.template.json b/.bcr/core/source.template.json
index 4a099d2d3..88571a2e1 100644
--- a/.bcr/core/source.template.json
+++ b/.bcr/core/source.template.json
@@ -1,5 +1,5 @@
 {
   "integrity": "",
   "strip_prefix": "{REPO}-{VERSION}/core",
-  "url": "https://github.com/{OWNER}/{REPO}/releases/download/{TAG}/${REPO}-${VERSION}.tar.gz"
+  "url": "https://github.com/{OWNER}/{REPO}/releases/download/{TAG}/{REPO}-{VERSION}.tar.gz"
 }