diff --git a/docs/shared_bindings_matrix.py b/docs/shared_bindings_matrix.py
index e89b47c871035..2dad572995386 100644
--- a/docs/shared_bindings_matrix.py
+++ b/docs/shared_bindings_matrix.py
@@ -170,9 +170,11 @@ def get_settings_from_makefile(port_dir, board_name):
     This means that the effect of all Makefile directives is taken
     into account, without having to re-encode the logic that sets them
     in this script, something that has proved error-prone
+
+    This list must explicitly include any setting queried by tools/ci_set_matrix.py.
     """
     contents = subprocess.run(
-        ["make", "-C", port_dir, "-f", "Makefile", f"BOARD={board_name}", "print-CFLAGS", "print-CIRCUITPY_BUILD_EXTENSIONS", "print-FROZEN_MPY_DIRS", "print-SRC_PATTERNS"],
+        ["make", "-C", port_dir, "-f", "Makefile", f"BOARD={board_name}", "print-CFLAGS", "print-CIRCUITPY_BUILD_EXTENSIONS", "print-FROZEN_MPY_DIRS", "print-SRC_PATTERNS", "print-SRC_SUPERVISOR"],
         encoding="utf-8",
         errors="replace",
         stdout=subprocess.PIPE,
diff --git a/tools/ci_set_matrix.py b/tools/ci_set_matrix.py
index e5ac80c91269c..15a6cb3ab87eb 100755
--- a/tools/ci_set_matrix.py
+++ b/tools/ci_set_matrix.py
@@ -189,23 +189,20 @@ def get_settings(board):
 
                     # Check frozen files to see if they are in each board
                     if file.startswith("frozen"):
-                        if file in settings.get("FROZEN_MPY_DIRS", ""):
+                        if file in settings["FROZEN_MPY_DIRS"]:
                             boards_to_build.add(board)
                             continue
 
                     # Check supervisor files
                     # This is useful for limiting workflow changes to the relevant boards
                     if file.startswith("supervisor"):
-                        if file in settings.get("SRC_SUPERVISOR", ""):
+                        if file in settings["SRC_SUPERVISOR"]:
                             boards_to_build.add(board)
                             continue
 
                         if file.startswith("supervisor/shared/web_workflow/static/"):
                             web_workflow = settings["CIRCUITPY_WEB_WORKFLOW"]
 
-                            while web_workflow.startswith("$("):
-                                web_workflow = settings[web_workflow[2:-1]]
-
                             if web_workflow != "0":
                                 boards_to_build.add(board)
                                 continue