diff --git a/Misc/NEWS.d/next/macOS/2021-01-28-06-44-47.bpo-43052.NoLlgY.rst b/Misc/NEWS.d/next/macOS/2021-01-28-06-44-47.bpo-43052.NoLlgY.rst
new file mode 100644
index 000000000000000..e33b5fd06f45332
--- /dev/null
+++ b/Misc/NEWS.d/next/macOS/2021-01-28-06-44-47.bpo-43052.NoLlgY.rst
@@ -0,0 +1 @@
+`_dyld_shared_cache_contains_path` now works with SYSTEM_VERSION_COMPAT=1
\ No newline at end of file
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 56ccc2f1e0b5da8..2a75f62421c44cd 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -1449,7 +1449,7 @@ static PyObject *py_dyld_shared_cache_contains_path(PyObject *self, PyObject *ar
      PyObject *name, *name2;
      char *name_str;
 
-     if (__builtin_available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)) {
+     if (__builtin_available(macOS 10.16, iOS 14.0, tvOS 14.0, watchOS 7.0, *)) {
          int r;
 
          if (!PyArg_ParseTuple(args, "O", &name))
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 4468fd08e17a53d..8edd4726d9b11d3 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -82,7 +82,7 @@
 #  define HAVE_SYMLINKAT_RUNTIME __builtin_available(macOS 10.10, iOS 8.0, *)
 #  define HAVE_FUTIMENS_RUNTIME __builtin_available(macOS 10.13, iOS 11.0, tvOS 11.0, watchOS 4.0, *)
 #  define HAVE_UTIMENSAT_RUNTIME __builtin_available(macOS 10.13, iOS 11.0, tvOS 11.0, watchOS 4.0, *)
-#  define HAVE_PWRITEV_RUNTIME __builtin_available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
+#  define HAVE_PWRITEV_RUNTIME __builtin_available(macOS 10.16, tvOS 14.0, watchOS 7.0, *)
 
 #  define HAVE_POSIX_SPAWN_SETSID_RUNTIME __builtin_available(macOS 10.15, *)