diff --git a/.github/workflows/Specs.yml b/.github/workflows/Specs.yml
index d4dbb89..e3e7862 100644
--- a/.github/workflows/Specs.yml
+++ b/.github/workflows/Specs.yml
@@ -5,7 +5,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [macos-10.15]
+        os: [macos-12]
         ruby: [2.7, 3.0.0]
 
     name: ${{ matrix.os }} / Ruby ${{ matrix.ruby }}
diff --git a/spec/git_spec.rb b/spec/git_spec.rb
index d93ded5..5cb96df 100644
--- a/spec/git_spec.rb
+++ b/spec/git_spec.rb
@@ -71,6 +71,13 @@ def fixture_url(name)
           FileUtils.cp_r(fixture('git-submodule-repo'), '/tmp/')
           options = { :git => fixture('git-repo'), :commit => 'd7f4104', :submodules => true }
           downloader = Downloader.for_target(tmp_folder, options)
+          downloader.instance_exec do
+            # Explicitly allow file transport as newer Git versions
+            # disable it by default
+            def target_git(*args)
+              super('-c', 'protocol.file.allow=always', *args)
+            end
+          end
           downloader.download
           tmp_folder('README').read.strip.should == 'added submodule'
           tmp_folder('submodule/README').read.strip.should == 'submodule'