diff --git a/src/libexpr/flake/flake.cc b/src/libexpr/flake/flake.cc
index 792e205dc..e26a838c2 100644
--- a/src/libexpr/flake/flake.cc
+++ b/src/libexpr/flake/flake.cc
@@ -203,6 +203,7 @@ static Flake readFlake(
     EvalState & state,
     const FlakeRef & originalRef,
     const FlakeRef & resolvedRef,
+    const FlakeRef & lockedRef,
     InputAccessor & accessor,
     const InputPath & lockRootPath)
 {
@@ -220,7 +221,7 @@ static Flake readFlake(
     Flake flake {
         .originalRef = originalRef,
         .resolvedRef = resolvedRef,
-        .lockedRef = resolvedRef, // FIXME
+        .lockedRef = lockedRef,
         .path = flakePath,
     };
 
@@ -319,9 +320,9 @@ static Flake getFlake(
         resolvedRef = originalRef.resolve(state.store);
     }
 
-    auto [accessor, input] = resolvedRef.input.lazyFetch(state.store);
+    auto [accessor, lockedRef] = resolvedRef.lazyFetch(state.store);
 
-    return readFlake(state, originalRef, resolvedRef, state.registerAccessor(accessor), lockRootPath);
+    return readFlake(state, originalRef, resolvedRef, lockedRef, state.registerAccessor(accessor), lockRootPath);
 }
 
 Flake getFlake(EvalState & state, const FlakeRef & originalRef, bool allowLookup, FlakeCache & flakeCache)
diff --git a/src/libexpr/flake/flakeref.cc b/src/libexpr/flake/flakeref.cc
index eede493f8..162656087 100644
--- a/src/libexpr/flake/flakeref.cc
+++ b/src/libexpr/flake/flakeref.cc
@@ -238,6 +238,12 @@ std::pair<fetchers::Tree, FlakeRef> FlakeRef::fetchTree(ref<Store> store) const
     return {std::move(tree), FlakeRef(std::move(lockedInput), subdir)};
 }
 
+std::pair<ref<InputAccessor>, FlakeRef> FlakeRef::lazyFetch(ref<Store> store) const
+{
+    auto [accessor, lockedInput] = input.lazyFetch(store);
+    return {accessor, FlakeRef(std::move(lockedInput), subdir)};
+}
+
 std::tuple<FlakeRef, std::string, OutputsSpec> parseFlakeRefWithFragmentAndOutputsSpec(
     const std::string & url,
     const std::optional<Path> & baseDir,
diff --git a/src/libexpr/flake/flakeref.hh b/src/libexpr/flake/flakeref.hh
index abc49ed70..bdf93b251 100644
--- a/src/libexpr/flake/flakeref.hh
+++ b/src/libexpr/flake/flakeref.hh
@@ -58,6 +58,8 @@ struct FlakeRef
     static FlakeRef fromAttrs(const fetchers::Attrs & attrs);
 
     std::pair<fetchers::Tree, FlakeRef> fetchTree(ref<Store> store) const;
+
+    std::pair<ref<InputAccessor>, FlakeRef> lazyFetch(ref<Store> store) const;
 };
 
 std::ostream & operator << (std::ostream & str, const FlakeRef & flakeRef);