diff --git a/src/libstore/fetchers/registry.cc b/src/libstore/fetchers/registry.cc
index 638e6e50a..69c80a5a9 100644
--- a/src/libstore/fetchers/registry.cc
+++ b/src/libstore/fetchers/registry.cc
@@ -127,10 +127,12 @@ static std::shared_ptr<Registry> getGlobalRegistry(ref<Store> store)
     static auto reg = [&]() {
         auto path = settings.flakeRegistry;
 
-        if (!hasPrefix(path, "/"))
-            // FIXME: register as GC root.
-            // FIXME: if download fails, use previous version if available.
-            path = store->toRealPath(downloadFile(store, path, "flake-registry.json", false).storePath);
+        if (!hasPrefix(path, "/")) {
+            auto storePath = downloadFile(store, path, "flake-registry.json", false).storePath;
+            if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>())
+                store2->addPermRoot(storePath, getCacheDir() + "/nix/flake-registry.json", true);
+            path = store->toRealPath(storePath);
+        }
 
         return Registry::read(path, Registry::Global);
     }();
diff --git a/tests/flakes.sh b/tests/flakes.sh
index 52f5fabc0..f2ebd7b0c 100644
--- a/tests/flakes.sh
+++ b/tests/flakes.sh
@@ -269,6 +269,7 @@ nix build -o $TEST_ROOT/result $flake3Dir#sth 2>&1 | grep 'unsupported edition'
 # Test whether registry caching works.
 nix flake list --flake-registry file://$registry | grep -q flake3
 mv $registry $registry.tmp
+nix-store --gc
 nix flake list --flake-registry file://$registry --refresh | grep -q flake3
 mv $registry.tmp $registry