diff --git a/numpy/core/src/multiarray/_multiarray_tests.c.src b/numpy/core/src/multiarray/_multiarray_tests.c.src
index 3811e87a8e34..3c8caefcef1f 100644
--- a/numpy/core/src/multiarray/_multiarray_tests.c.src
+++ b/numpy/core/src/multiarray/_multiarray_tests.c.src
@@ -677,11 +677,12 @@ create_custom_field_dtype(PyObject *NPY_UNUSED(mod), PyObject *args)
                 "invalid error argument to test function.");
     }
     if (PyArray_RegisterDataType(dtype) < 0) {
-        /* Fix original type in the error_path == 2 case. */
+        /* Fix original type in the error_path == 2 case and delete it */
         Py_SET_TYPE(dtype, original_type);
+        Py_DECREF(dtype);
         return NULL;
     }
-    Py_INCREF(dtype);
+    Py_INCREF(dtype);  /* hold on to the original (leaks a reference) */
     return (PyObject *)dtype;
 }
 
diff --git a/numpy/core/src/multiarray/item_selection.c b/numpy/core/src/multiarray/item_selection.c
index 8052e24e424b..b279ffc2f1ba 100644
--- a/numpy/core/src/multiarray/item_selection.c
+++ b/numpy/core/src/multiarray/item_selection.c
@@ -576,6 +576,10 @@ PyArray_PutMask(PyArrayObject *self, PyObject* values0, PyObject* mask0)
         return NULL;
     }
 
+    if (PyArray_FailUnlessWriteable(self, "putmask: output array") < 0) {
+        return NULL;
+    }
+
     mask = (PyArrayObject *)PyArray_FROM_OTF(mask0, NPY_BOOL,
                                 NPY_ARRAY_CARRAY | NPY_ARRAY_FORCECAST);
     if (mask == NULL) {
diff --git a/numpy/core/src/multiarray/mapping.c b/numpy/core/src/multiarray/mapping.c
index cb5c3823dccf..d64962f87150 100644
--- a/numpy/core/src/multiarray/mapping.c
+++ b/numpy/core/src/multiarray/mapping.c
@@ -3194,9 +3194,10 @@ PyArray_MapIterNew(npy_index_info *indices , int index_num, int index_type,
     }
 
     PyObject *shape2 = convert_shape_to_string(mit->nd, mit->dimensions, "");
-    if (shape2 == NULL)
+    if (shape2 == NULL) {
         Py_DECREF(shape1);
         goto finish;
+    }
 
     PyErr_Format(PyExc_ValueError,
             "shape mismatch: value array of shape %S could not be broadcast "
diff --git a/numpy/core/src/multiarray/scalartypes.c.src b/numpy/core/src/multiarray/scalartypes.c.src
index d018fccbbd22..e480628e710c 100644
--- a/numpy/core/src/multiarray/scalartypes.c.src
+++ b/numpy/core/src/multiarray/scalartypes.c.src
@@ -2395,6 +2395,10 @@ gentype_arrtype_getbuffer(PyObject *self, Py_buffer *view, int flags)
                 self);
         return -1;
     }
+    if ((flags & PyBUF_WRITEABLE) == PyBUF_WRITEABLE) {
+        PyErr_SetString(PyExc_BufferError, "scalar buffer is readonly");
+        return -1;
+    }
     PyArray_Descr *descr = PyArray_DescrFromScalar(self);
     if (descr == NULL) {
         return -1;
@@ -2413,6 +2417,7 @@ gentype_arrtype_getbuffer(PyObject *self, Py_buffer *view, int flags)
     view->shape = NULL;
     view->strides = NULL;
     view->suboffsets = NULL;
+    view->readonly = 1;  /* assume general (user) scalars are readonly. */
     Py_INCREF(self);
     view->obj = self;
     view->buf = scalar_value(self, descr);
@@ -2444,6 +2449,7 @@ static int
 @name@_getbuffer(PyObject *self, Py_buffer *view, int flags)
 {
     if ((flags & PyBUF_WRITEABLE) == PyBUF_WRITEABLE) {
+        PyErr_SetString(PyExc_BufferError, "scalar buffer is readonly");
         return -1;
     }
     Py@Name@ScalarObject *scalar = (Py@Name@ScalarObject *)self;
@@ -2456,6 +2462,7 @@ static int
     view->shape = NULL;
     view->strides = NULL;
     view->suboffsets = NULL;
+    view->readonly = 1;
     Py_INCREF(self);
     view->obj = self;
     view->buf = &(scalar->obval);
@@ -2482,6 +2489,7 @@ static int
 unicode_getbuffer(PyObject *self, Py_buffer *view, int flags)
 {
     if ((flags & PyBUF_WRITEABLE) == PyBUF_WRITEABLE) {
+        PyErr_SetString(PyExc_BufferError, "scalar buffer is readonly");
         return -1;
     }
     PyUnicodeScalarObject *scalar = (PyUnicodeScalarObject *)self;
@@ -2493,6 +2501,7 @@ unicode_getbuffer(PyObject *self, Py_buffer *view, int flags)
     view->shape = NULL;
     view->strides = NULL;
     view->suboffsets = NULL;
+    view->readonly = 1;
     Py_INCREF(self);
     view->obj = self;
 
@@ -2522,7 +2531,7 @@ unicode_getbuffer(PyObject *self, Py_buffer *view, int flags)
         view->format = scalar->buffer_fmt;
     }
     else {
-        scalar->buffer_fmt = PyObject_Malloc(22);
+        scalar->buffer_fmt = PyMem_Malloc(22);
         if (scalar->buffer_fmt == NULL) {
             Py_SETREF(view->obj, NULL);
             return -1;
@@ -2549,6 +2558,7 @@ static int
 @name@_getbuffer(PyObject *self, Py_buffer *view, int flags)
 {
     if ((flags & PyBUF_WRITEABLE) == PyBUF_WRITEABLE) {
+        PyErr_SetString(PyExc_BufferError, "scalar buffer is readonly");
         return -1;
     }
     Py@Name@ScalarObject *scalar = (Py@Name@ScalarObject *)self;
@@ -2560,6 +2570,7 @@ static int
     view->shape = &length;
     view->strides = NULL;
     view->suboffsets = NULL;
+    view->readonly = 1;
     Py_INCREF(self);
     view->obj = self;
 
@@ -2651,6 +2662,7 @@ unicode_arrtype_dealloc(PyObject *v)
 {
     /* note: may be null if it was never requested */
     PyMem_Free(PyArrayScalar_VAL(v, Unicode));
+    PyMem_Free(((PyUnicodeScalarObject *)v)->buffer_fmt);
     /* delegate to the base class */
     PyUnicode_Type.tp_dealloc(v);
 }
diff --git a/numpy/core/tests/test_multiarray.py b/numpy/core/tests/test_multiarray.py
index 12306cbb883d..306c7f59922d 100644
--- a/numpy/core/tests/test_multiarray.py
+++ b/numpy/core/tests/test_multiarray.py
@@ -4643,6 +4643,12 @@ def test_overlaps(self):
         np.putmask(x[1:4], x[:3], [True, False, True])
         assert_equal(x, np.array([True, True, True, True]))
 
+    def test_writeable(self):
+        a = np.arange(12)
+        a.setflags(write = False)
+
+        with pytest.raises(ValueError):
+            np.putmask(a, a >= 3, 2)
 
 class TestTake:
     def tst_basic(self, x):
@@ -7350,9 +7356,9 @@ def test_export_flags(self):
     def test_export_and_pickle_user_dtype(self, obj, error):
         # User dtypes should export successfully when FORMAT was not requested.
         with pytest.raises(error):
-            _multiarray_tests.get_buffer_info(obj, ("STRIDED", "FORMAT"))
+            _multiarray_tests.get_buffer_info(obj, ("STRIDED_RO", "FORMAT"))
 
-        _multiarray_tests.get_buffer_info(obj, ("STRIDED",))
+        _multiarray_tests.get_buffer_info(obj, ("STRIDED_RO",))
 
         # This is currently also necessary to implement pickling:
         pickle_obj = pickle.dumps(obj)
diff --git a/numpy/core/tests/test_scalarbuffer.py b/numpy/core/tests/test_scalarbuffer.py
index 574c56864bb7..851cd3081aee 100644
--- a/numpy/core/tests/test_scalarbuffer.py
+++ b/numpy/core/tests/test_scalarbuffer.py
@@ -3,6 +3,7 @@
 """
 import numpy as np
 from numpy.core._rational_tests import rational
+from numpy.core._multiarray_tests import get_buffer_info
 import pytest
 
 from numpy.testing import assert_, assert_equal, assert_raises
@@ -52,10 +53,20 @@ def test_scalar_dim(self, scalar):
         assert_equal(mv_x.suboffsets, ())
 
     @pytest.mark.parametrize('scalar, code', scalars_and_codes, ids=codes_only)
-    def test_scalar_known_code(self, scalar, code):
+    def test_scalar_code_and_properties(self, scalar, code):
         x = scalar()
+        expected = dict(strides=(), itemsize=x.dtype.itemsize, ndim=0,
+                        shape=(), format=code, readonly=True)
+
         mv_x = memoryview(x)
-        assert_equal(mv_x.format, code)
+        print(mv_x.readonly, self._as_dict(mv_x))
+        assert self._as_dict(mv_x) == expected
+
+    @pytest.mark.parametrize('scalar', scalars_only, ids=codes_only)
+    def test_scalar_buffers_readonly(self, scalar):
+        x = scalar()
+        with pytest.raises(BufferError, match="scalar buffer is readonly"):
+            get_buffer_info(x, ["WRITABLE"])
 
     def test_void_scalar_structured_data(self):
         dt = np.dtype([('name', np.unicode_, 16), ('grades', np.float64, (2,))])
@@ -77,9 +88,14 @@ def test_void_scalar_structured_data(self):
         assert_equal(mv_x.itemsize, mv_a.itemsize)
         assert_equal(mv_x.format, mv_a.format)
 
+        # Check that we do not allow writeable buffer export (technically
+        # we could allow it sometimes here...)
+        with pytest.raises(BufferError, match="scalar buffer is readonly"):
+            get_buffer_info(x, ["WRITABLE"])
+
     def _as_dict(self, m):
         return dict(strides=m.strides, shape=m.shape, itemsize=m.itemsize,
-                    ndim=m.ndim, format=m.format)
+                    ndim=m.ndim, format=m.format, readonly=m.readonly)
 
     def test_datetime_memoryview(self):
         # gh-11656
@@ -88,7 +104,7 @@ def test_datetime_memoryview(self):
         dt1 = np.datetime64('2016-01-01')
         dt2 = np.datetime64('2017-01-01')
         expected = dict(strides=(1,), itemsize=1, ndim=1, shape=(8,),
-                        format='B')
+                        format='B', readonly=True)
         v = memoryview(dt1)
         assert self._as_dict(v) == expected
 
@@ -100,6 +116,10 @@ def test_datetime_memoryview(self):
         # Fails to create a PEP 3118 valid buffer
         assert_raises((ValueError, BufferError), memoryview, a[0])
 
+        # Check that we do not allow writeable buffer export
+        with pytest.raises(BufferError, match="scalar buffer is readonly"):
+            get_buffer_info(dt1, ["WRITABLE"])
+
     @pytest.mark.parametrize('s', [
         pytest.param("\x32\x32", id="ascii"),
         pytest.param("\uFE0F\uFE0F", id="basic multilingual"),
@@ -109,7 +129,8 @@ def test_str_ucs4(self, s):
         s = np.str_(s)  # only our subclass implements the buffer protocol
 
         # all the same, characters always encode as ucs4
-        expected = dict(strides=(), itemsize=8, ndim=0, shape=(), format='2w')
+        expected = dict(strides=(), itemsize=8, ndim=0, shape=(), format='2w',
+                        readonly=True)
 
         v = memoryview(s)
         assert self._as_dict(v) == expected
@@ -119,7 +140,15 @@ def test_str_ucs4(self, s):
 
         assert_equal(code_points, [ord(c) for c in s])
 
+        # Check that we do not allow writeable buffer export
+        with pytest.raises(BufferError, match="scalar buffer is readonly"):
+            get_buffer_info(s, ["WRITABLE"])
+
     def test_user_scalar_fails_buffer(self):
         r = rational(1)
         with assert_raises(TypeError):
             memoryview(r)
+
+        # Check that we do not allow writeable buffer export
+        with pytest.raises(BufferError, match="scalar buffer is readonly"):
+            get_buffer_info(r, ["WRITABLE"])
\ No newline at end of file
diff --git a/test_requirements.txt b/test_requirements.txt
index 2ca10be5d16d..97d06a0cfaec 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -1,7 +1,7 @@
 cython==0.29.21
 wheel
 setuptools<49.2.0
-hypothesis==5.41.3
+hypothesis==5.41.4
 pytest==6.0.2
 pytz==2020.4
 pytest-cov==2.10.1
diff --git a/tools/openblas_support.py b/tools/openblas_support.py
index c0e9dddab467..50837177b680 100644
--- a/tools/openblas_support.py
+++ b/tools/openblas_support.py
@@ -84,8 +84,6 @@
     "f68fea21fbc73d06b7566057cad2ed8c7c0eb71fabf9ed8a609f86e5bc60ce5e",
     "openblas64_-v0.3.10-manylinux2014_aarch64.tar.gz":
     "15e6eed8cb0df8b88e52baa136ffe1769c517e9de7bcdfd81ec56420ae1069e9",
-    "openblas64_-v0.3.10-win_amd64-gcc_7_1_0.zip":
-    "aea3f9c8bdfe0b837f0d2739a6c755b12b6838f6c983e4ede71b4e1b576e6e77",
 }