diff --git a/CHANGELOG.md b/CHANGELOG.md
index 70dd7987f..8a1995158 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ All notable changes to this project will be documented in this file.
 - Zigbee support for decimal Voltage/Current/Power on power metering plugs
 - Command ``UrlFetch <url>`` to download a file to filesystem
 - Zigbee basic support for Green Power
+- Berry add ``introspect.setmodule(name:string, value:any) -> nil``
 
 ### Changed
 - ESP32 Increase number of button GPIOs from 8 to 28 (#16518)
diff --git a/lib/libesp32/berry/src/be_introspectlib.c b/lib/libesp32/berry/src/be_introspectlib.c
index 1e5b521d3..28f506d18 100644
--- a/lib/libesp32/berry/src/be_introspectlib.c
+++ b/lib/libesp32/berry/src/be_introspectlib.c
@@ -66,10 +66,25 @@ static void m_findmember_protected(bvm *vm, void* data)
 static int m_findmember(bvm *vm)
 {
     int top = be_top(vm);
-    if (top >= 2 && (be_isinstance(vm, 1) || be_ismodule(vm, 1) || be_isclass(vm, 1)) && be_isstring(vm, 2)) {
-        int ret = be_execprotected(vm, &m_findmember_protected, (void*) be_tostring(vm, 2));
-        if (ret == BE_OK) {
-            be_return(vm);
+    bbool protected = btrue; /* run protected, i.e. don't raise an exception if not found */
+    if (top >= 3) {
+        protected = !be_tobool(vm, 3);
+    }
+    if (top >= 2) {
+        if (protected && (be_isinstance(vm, 1) || be_ismodule(vm, 1) || be_isclass(vm, 1)) && be_isstring(vm, 2)) {
+            int ret = be_execprotected(vm, &m_findmember_protected, (void*) be_tostring(vm, 2));
+            if (ret == BE_OK) {
+                be_return(vm);
+            }
+        } else {
+            /* run unprotected */
+            if (be_getmember(vm, 1, be_tostring(vm, 2))) {
+                be_return(vm);
+            } else {
+                /* not found, return module 'undefined' */
+                be_getmodule(vm, "undefined");
+                be_return(vm);
+            }
         }
     }
     be_return_nil(vm);
@@ -143,6 +158,20 @@ static int m_getmodule(bvm *vm)
     be_return_nil(vm);
 }
 
+/* set or chang the cached value for the named module, this allows monkey patching. **USE WITH CARE** */
+static int m_setmodule(bvm *vm)
+{
+    int top = be_top(vm);
+    if (top >= 2) {
+        bvalue *v = be_indexof(vm, 1);
+        if (var_isstr(v)) {
+            be_pushvalue(vm, 2);  /* ensure the second arg is at top of stack */
+            be_cache_module(vm, var_tostr(v));
+        }
+    }
+    be_return_nil(vm);
+}
+
 /* checks if the function (berry bytecode bproto only) is hinted as a method */
 static int m_ismethod(bvm *vm)
 {
@@ -167,6 +196,7 @@ be_native_module_attr_table(introspect) {
     be_native_module_function("set", m_setmember),
 
     be_native_module_function("module", m_getmodule),
+    be_native_module_function("setmodule", m_setmodule),
 
     be_native_module_function("toptr", m_toptr),
     be_native_module_function("fromptr", m_fromptr),
@@ -184,6 +214,7 @@ module introspect (scope: global, depend: BE_USE_INTROSPECT_MODULE) {
     set, func(m_setmember)
 
     module, func(m_getmodule)
+    setmodule, func(m_setmodule)
 
     toptr, func(m_toptr)
     fromptr, func(m_fromptr)
diff --git a/lib/libesp32/berry/src/be_module.c b/lib/libesp32/berry/src/be_module.c
index bf7c7720f..2d5e826b6 100644
--- a/lib/libesp32/berry/src/be_module.c
+++ b/lib/libesp32/berry/src/be_module.c
@@ -245,7 +245,7 @@ static bvalue* load_cached(bvm *vm, bstring *path)
     return v;
 }
 
-static void cache_module(bvm *vm, bstring *name)
+void be_cache_module(bvm *vm, bstring *name)
 {
     bvalue *v;
     if (vm->module.loaded == NULL) {
@@ -282,7 +282,7 @@ int be_module_load(bvm *vm, bstring *path)
         if (res == BE_OK) {
             /* on first load of the module, try running the '()' function */
             module_init(vm);
-            cache_module(vm, path);
+            be_cache_module(vm, path);
         }
     }
     return res;
diff --git a/lib/libesp32/berry/src/be_module.h b/lib/libesp32/berry/src/be_module.h
index 4f9b869de..26760660f 100644
--- a/lib/libesp32/berry/src/be_module.h
+++ b/lib/libesp32/berry/src/be_module.h
@@ -34,6 +34,7 @@ typedef struct bmodule {
 bmodule* be_module_new(bvm *vm);
 void be_module_delete(bvm *vm, bmodule *module);
 int be_module_load(bvm *vm, bstring *path);
+void be_cache_module(bvm *vm, bstring *name);
 int be_module_attr(bvm *vm, bmodule *module, bstring *attr, bvalue *dst);
 bbool be_module_setmember(bvm *vm, bmodule *module, bstring *attr, bvalue *src);
 const char* be_module_name(bmodule *module);
diff --git a/lib/libesp32/berry/tests/module.be b/lib/libesp32/berry/tests/module.be
new file mode 100644
index 000000000..2c59aa4b7
--- /dev/null
+++ b/lib/libesp32/berry/tests/module.be
@@ -0,0 +1,45 @@
+# test for monkey patching of modules
+
+import string
+import introspect
+
+var string_orig = string
+
+introspect.setmodule("string", 42)
+import string
+assert(string == 42)
+
+# set back original value
+introspect.setmodule("string", string_orig)
+import string
+assert(type(string) == 'module')
+assert(str(string) == '<module: string>')
+
+#
+# demo, how to monkey patch string with a new function `foo()` returning `bar`
+#
+import string
+import introspect
+var string_orig = string            # keep a copy of the original string module
+var string_alt = module('string')   # create a new module
+
+# function `super()` is a closure to capture the original value of string
+string_alt.super = def()
+    return string_orig
+end
+
+# function `member()` is a clousre to capture the original value of string module
+string_alt.member = def(k)
+    import introspect
+    return introspect.get(string_orig, k, true)
+end
+
+string_alt.foo = def() return 'bar' end
+
+# replace the entry for module "string", from now on each `import string` will use `string_alt`
+introspect.setmodule("string", string_alt)
+import string
+
+# test the new string module
+assert(string.tolower('abCD') == 'abcd')
+assert(string.foo() == 'bar')