diff --git a/.gitignore b/.gitignore
index 50f3249..5ca0c96 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,3 +7,4 @@ venv/
 
 .ipynb_checkpoints/
 __pycache__/
+.mpy_ld_cache/
diff --git a/requirements.txt b/requirements.txt
index 5d13c4b..6ee4e56 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-emlearn>=0.21.0
+emlearn>=0.21.1
 scikit-learn>=1.0.0
 ar>=1.0.0
 pyelftools>=0.31
diff --git a/src/emlearn_iir/iir_filter.c b/src/emlearn_iir/iir_filter.c
index ac62f31..0434ea6 100644
--- a/src/emlearn_iir/iir_filter.c
+++ b/src/emlearn_iir/iir_filter.c
@@ -1,5 +1,9 @@
 // Include the header file to get access to the MicroPython API
+#ifdef MICROPY_ENABLE_DYNRUNTIME
 #include "py/dynruntime.h"
+#else
+#include "py/runtime.h"
+#endif
 
 #include <eml_iir.h>
 
@@ -29,7 +33,11 @@ typedef struct _mp_obj_iir_filter_t {
     EmlIIR filter;
 } mp_obj_iir_filter_t;
 
+#if MICROPY_ENABLE_DYNRUNTIME
 mp_obj_full_type_t iir_filter_type;
+#else
+static const mp_obj_type_t iir_filter_type;
+#endif
 
 // Create a new instance
 static mp_obj_t iir_filter_new(mp_obj_t array_obj) {
@@ -55,17 +63,17 @@ static mp_obj_t iir_filter_new(mp_obj_t array_obj) {
     self->n_stages = n_values / 6;
 
     self->states_length = self->n_stages * 4;
-    self->states = (float *)m_malloc(sizeof(float)*self->states_length);
+    self->states = m_new(float, self->states_length);
 
     self->coefficients_length = n_values;
-    self->coefficients = (float *)m_malloc(sizeof(float)*self->coefficients_length);
+    self->coefficients = m_new(float, self->coefficients_length);
     memcpy((float *)self->coefficients, values, sizeof(float)*self->coefficients_length);
 
 
     const EmlError err = eml_iir_check(*self);
     if (err != EmlOk) {
-        m_free(self->states);
-        m_free((float *)self->coefficients);
+        m_del(float, self->states, self->states_length);
+        m_del(float, (float *)self->coefficients, self->coefficients_length);
         mp_raise_ValueError(MP_ERROR_TEXT("EmlError"));
     }
 
@@ -80,9 +88,8 @@ static mp_obj_t iir_filter_del(mp_obj_t self_obj) {
     EmlIIR *self = &o->filter;
 
     // free allocated data
-    m_free(self->states);
-    m_free((float *)self->coefficients);
-
+    m_del(float, self->states, self->states_length);
+    m_del(float, (float *)self->coefficients, self->coefficients_length);
 
     return mp_const_none;
 }
@@ -114,6 +121,7 @@ static mp_obj_t iir_filter_run(mp_obj_t self_obj, mp_obj_t array_obj) {
 static MP_DEFINE_CONST_FUN_OBJ_2(iir_filter_run_obj, iir_filter_run);
 
 
+#ifdef MICROPY_ENABLE_DYNRUNTIME
 mp_map_elem_t iir_locals_dict_table[2];
 static MP_DEFINE_CONST_DICT(iir_locals_dict, iir_locals_dict_table);
 
@@ -136,4 +144,35 @@ mp_obj_t mpy_init(mp_obj_fun_bc_t *self, size_t n_args, size_t n_kw, mp_obj_t *a
     // This must be last, it restores the globals dict
     MP_DYNRUNTIME_INIT_EXIT
 }
+#else
+
+
+// Define a class
+static const mp_rom_map_elem_t emlearn_iir_filter_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_run), MP_ROM_PTR(&iir_filter_run_obj) },
+    { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&iir_filter_del_obj) }
+};
+static MP_DEFINE_CONST_DICT(emlearn_iir_filter_locals_dict, emlearn_iir_filter_locals_dict_table);
+
+static MP_DEFINE_CONST_OBJ_TYPE(
+    iir_filter_type,
+    MP_QSTR_emliir,
+    MP_TYPE_FLAG_NONE,
+    locals_dict, &emlearn_iir_filter_locals_dict
+);
 
+// Define module object.
+static const mp_rom_map_elem_t emlearn_iir_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_new), MP_ROM_PTR(&iir_filter_new_obj) },
+};
+static MP_DEFINE_CONST_DICT(emlearn_iir_globals, emlearn_iir_globals_table);
+
+const mp_obj_module_t emlearn_iir_cmodule = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t *)&emlearn_iir_globals,
+};
+
+MP_REGISTER_MODULE(MP_QSTR_emlearn_iir, emlearn_iir_cmodule);
+
+
+#endif
diff --git a/src/emlearn_iir/micropython.mk b/src/emlearn_iir/micropython.mk
new file mode 100644
index 0000000..40d8ad6
--- /dev/null
+++ b/src/emlearn_iir/micropython.mk
@@ -0,0 +1,9 @@
+MOD_DIR := $(USERMOD_DIR)
+
+# Add all C files to SRC_USERMOD.
+SRC_USERMOD_C += $(MOD_DIR)/iir_filter.c
+
+EMLEARN_DIR := $(shell python3 -c "import emlearn; print(emlearn.includedir)")
+
+# We can add our module folder to include paths if needed
+CFLAGS_USERMOD += -I$(EMLEARN_DIR)
diff --git a/src/emlearn_trees/Makefile b/src/emlearn_trees/Makefile
index d1a71cf..01220c9 100644
--- a/src/emlearn_trees/Makefile
+++ b/src/emlearn_trees/Makefile
@@ -32,6 +32,6 @@ $(DIST_FILE): $(MOD).mpy $(DIST_DIR)
 # Include to get the rules for compiling and linking the module
 include $(MPY_DIR)/py/dynruntime.mk
 
-CFLAGS += -I$(EMLEARN_DIR)
+CFLAGS += -I$(EMLEARN_DIR) -DDYNAMIC_RUNTIME=1
 
 dist: $(DIST_FILE)
diff --git a/src/emlearn_trees/micropython.mk b/src/emlearn_trees/micropython.mk
new file mode 100644
index 0000000..066419a
--- /dev/null
+++ b/src/emlearn_trees/micropython.mk
@@ -0,0 +1,9 @@
+MOD_DIR := $(USERMOD_DIR)
+
+# Add all C files to SRC_USERMOD.
+SRC_USERMOD_C += $(MOD_DIR)/trees.c
+
+EMLEARN_DIR := $(shell python3 -c "import emlearn; print(emlearn.includedir)")
+
+# We can add our module folder to include paths if needed
+CFLAGS_USERMOD += -I$(EMLEARN_DIR)
diff --git a/src/emlearn_trees/trees.c b/src/emlearn_trees/trees.c
index b98ac76..8cb3f45 100644
--- a/src/emlearn_trees/trees.c
+++ b/src/emlearn_trees/trees.c
@@ -1,5 +1,10 @@
 // Include the header file to get access to the MicroPython API
+
+#ifdef MICROPY_ENABLE_DYNRUNTIME
 #include "py/dynruntime.h"
+#else
+#include "py/runtime.h"
+#endif
 
 #define EML_TREES_REGRESSION_ENABLE 0
 #include <eml_trees.h>
@@ -33,7 +38,11 @@ typedef struct _mp_obj_trees_builder_t {
     EmlTreesBuilder builder;
 } mp_obj_trees_builder_t;
 
+#if MICROPY_ENABLE_DYNRUNTIME
 mp_obj_full_type_t trees_builder_type;
+#else
+static const mp_obj_type_t trees_builder_type;
+#endif
 
 // Create a new tree builder
 static mp_obj_t builder_new(mp_obj_t trees_obj, mp_obj_t nodes_obj, mp_obj_t leaves_obj) {
@@ -58,9 +67,9 @@ static mp_obj_t builder_new(mp_obj_t trees_obj, mp_obj_t nodes_obj, mp_obj_t lea
     self->max_leaves = max_leaves;
 
     // create storage for trees
-    EmlTreesNode *nodes = (EmlTreesNode *)m_malloc(sizeof(EmlTreesNode)*max_nodes);
-    int32_t *roots = (int32_t *)m_malloc(sizeof(int32_t)*max_trees);
-    uint8_t *leaves = (uint8_t *)m_malloc(sizeof(uint8_t)*max_leaves);
+    EmlTreesNode *nodes = m_new(EmlTreesNode, self->max_nodes);
+    int32_t *roots = m_new(int32_t, self->max_trees);
+    uint8_t *leaves = m_new(uint8_t, self->max_leaves);
 
 #if EMLEARN_MICROPYTHON_DEBUG
     mp_printf(&mp_plat_print, "emltrees nodes=%p roots=%p builder=%p\n", nodes, roots, self);
@@ -91,9 +100,9 @@ static mp_obj_t builder_del(mp_obj_t trees_obj) {
     EmlTreesBuilder *self = &o->builder;
 
     // free allocated data
-    m_free(self->trees.nodes);
-    m_free(self->trees.tree_roots);
-    m_free(self->trees.leaves);
+    m_del(EmlTreesNode, self->trees.nodes, self->max_nodes);
+    m_del(int32_t, self->trees.tree_roots, self->max_nodes);
+    m_del(uint8_t, self->trees.leaves, self->max_leaves);
 
 #if EMLEARN_MICROPYTHON_DEBUG
     mp_printf(&mp_plat_print, "emltrees del \n");
@@ -261,6 +270,7 @@ static mp_obj_t builder_predict(mp_obj_t self_obj, mp_obj_t features_obj, mp_obj
 static MP_DEFINE_CONST_FUN_OBJ_3(builder_predict_obj, builder_predict);
 
 
+#ifdef MICROPY_ENABLE_DYNRUNTIME
 mp_map_elem_t trees_locals_dict_table[7];
 static MP_DEFINE_CONST_DICT(trees_locals_dict, trees_locals_dict_table);
 
@@ -289,3 +299,40 @@ mp_obj_t mpy_init(mp_obj_fun_bc_t *self, size_t n_args, size_t n_kw, mp_obj_t *a
     MP_DYNRUNTIME_INIT_EXIT
 }
 
+#else
+
+
+// Define the tree builder class
+static const mp_rom_map_elem_t emlearn_trees_builder_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_predict), MP_ROM_PTR(&builder_predict_obj) },
+    { MP_ROM_QSTR(MP_QSTR_addnode), MP_ROM_PTR(&builder_addnode_obj) },
+    { MP_ROM_QSTR(MP_QSTR_addroot), MP_ROM_PTR(&builder_addroot_obj) },
+    { MP_ROM_QSTR(MP_QSTR_addleaf), MP_ROM_PTR(&builder_addleaf_obj) },
+    { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&builder_del_obj) },
+    { MP_ROM_QSTR(MP_QSTR_setdata), MP_ROM_PTR(&builder_setdata_obj) },
+    { MP_ROM_QSTR(MP_QSTR_outputs), MP_ROM_PTR(&builder_get_outputs_obj) },
+};
+static MP_DEFINE_CONST_DICT(emlearn_trees_builder_locals_dict, emlearn_trees_builder_locals_dict_table);
+
+static MP_DEFINE_CONST_OBJ_TYPE(
+    trees_builder_type,
+    MP_QSTR_emltrees,
+    MP_TYPE_FLAG_NONE,
+    locals_dict, &emlearn_trees_builder_locals_dict
+);
+
+// Define module object.
+static const mp_rom_map_elem_t emlearn_trees_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_new), MP_ROM_PTR(&builder_new_obj) },
+};
+static MP_DEFINE_CONST_DICT(emlearn_trees_globals, emlearn_trees_globals_table);
+
+const mp_obj_module_t emlearn_trees_cmodule = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t *)&emlearn_trees_globals,
+};
+
+MP_REGISTER_MODULE(MP_QSTR_emlearn_trees, emlearn_trees_cmodule);
+
+#endif
+