diff --git a/ports/espressif/Makefile b/ports/espressif/Makefile
index ce121ccad0..0febf307ff 100644
--- a/ports/espressif/Makefile
+++ b/ports/espressif/Makefile
@@ -157,7 +157,12 @@ ifeq ($(DEBUG), 1)
   # CFLAGS += -fno-inline -fno-ipa-sra
 else
   CFLAGS += -DNDEBUG -ggdb3
-  OPTIMIZATION_FLAGS ?= -O2
+	ifeq ($(IDF_TARGET_ARCH),xtensa)
+	  OPTIMIZATION_FLAGS ?= -O2
+	else
+		# RISC-V is larger than xtensa so do -Os for it
+	  OPTIMIZATION_FLAGS ?= -Os
+	endif
   # TODO: Test with -flto
   ### CFLAGS += -flto
 endif
diff --git a/ports/espressif/common-hal/_bleio/Characteristic.c b/ports/espressif/common-hal/_bleio/Characteristic.c
index 6c81731aa7..161e17ea1a 100644
--- a/ports/espressif/common-hal/_bleio/Characteristic.c
+++ b/ports/espressif/common-hal/_bleio/Characteristic.c
@@ -75,6 +75,7 @@ void common_hal_bleio_characteristic_construct(bleio_characteristic_obj_t *self,
     //     mp_raise_ValueError_varg(translate("max_length must be 0-%d when fixed_length is %s"),
     //         max_length_max, fixed_length ? "True" : "False");
     // }
+    // TODO: Implement this.
     self->max_length = max_length;
     self->fixed_length = fixed_length;
 
@@ -97,6 +98,7 @@ bleio_service_obj_t *common_hal_bleio_characteristic_get_service(bleio_character
 }
 
 size_t common_hal_bleio_characteristic_get_value(bleio_characteristic_obj_t *self, uint8_t *buf, size_t len) {
+    // TODO: Implement this.
     return 0;
 }
 
@@ -105,6 +107,7 @@ size_t common_hal_bleio_characteristic_get_max_length(bleio_characteristic_obj_t
 }
 
 void common_hal_bleio_characteristic_set_value(bleio_characteristic_obj_t *self, mp_buffer_info_t *bufinfo) {
+    // TODO: Implement this.
 }
 
 bleio_uuid_obj_t *common_hal_bleio_characteristic_get_uuid(bleio_characteristic_obj_t *self) {
@@ -116,8 +119,9 @@ bleio_characteristic_properties_t common_hal_bleio_characteristic_get_properties
 }
 
 void common_hal_bleio_characteristic_add_descriptor(bleio_characteristic_obj_t *self, bleio_descriptor_obj_t *descriptor) {
+    // TODO: Implement this.
 }
 
 void common_hal_bleio_characteristic_set_cccd(bleio_characteristic_obj_t *self, bool notify, bool indicate) {
-
+    // TODO: Implement this.
 }
diff --git a/ports/espressif/common-hal/_bleio/CharacteristicBuffer.c b/ports/espressif/common-hal/_bleio/CharacteristicBuffer.c
index dce2053282..bc6619cef4 100644
--- a/ports/espressif/common-hal/_bleio/CharacteristicBuffer.c
+++ b/ports/espressif/common-hal/_bleio/CharacteristicBuffer.c
@@ -65,15 +65,17 @@ void common_hal_bleio_characteristic_buffer_construct(bleio_characteristic_buffe
 }
 
 uint32_t common_hal_bleio_characteristic_buffer_read(bleio_characteristic_buffer_obj_t *self, uint8_t *data, size_t len, int *errcode) {
-
+    // TODO: Implement this.
     return 0;
 }
 
 uint32_t common_hal_bleio_characteristic_buffer_rx_characters_available(bleio_characteristic_buffer_obj_t *self) {
+    // TODO: Implement this.
     return 0;
 }
 
 void common_hal_bleio_characteristic_buffer_clear_rx_buffer(bleio_characteristic_buffer_obj_t *self) {
+    // TODO: Implement this.
 }
 
 bool common_hal_bleio_characteristic_buffer_deinited(bleio_characteristic_buffer_obj_t *self) {
@@ -81,6 +83,7 @@ bool common_hal_bleio_characteristic_buffer_deinited(bleio_characteristic_buffer
 }
 
 void common_hal_bleio_characteristic_buffer_deinit(bleio_characteristic_buffer_obj_t *self) {
+    // TODO: Implement this.
 }
 
 bool common_hal_bleio_characteristic_buffer_connected(bleio_characteristic_buffer_obj_t *self) {
diff --git a/ports/espressif/common-hal/_bleio/Connection.c b/ports/espressif/common-hal/_bleio/Connection.c
index 647808fe57..2a96c2e189 100644
--- a/ports/espressif/common-hal/_bleio/Connection.c
+++ b/ports/espressif/common-hal/_bleio/Connection.c
@@ -64,13 +64,15 @@ bool common_hal_bleio_connection_get_connected(bleio_connection_obj_t *self) {
 }
 
 void common_hal_bleio_connection_disconnect(bleio_connection_internal_t *self) {
+    // TODO: Implement this.
 }
 
 void common_hal_bleio_connection_pair(bleio_connection_internal_t *self, bool bond) {
-
+    // TODO: Implement this.
 }
 
 mp_float_t common_hal_bleio_connection_get_connection_interval(bleio_connection_internal_t *self) {
+    // TODO: Implement this.
     while (self->conn_params_updating && !mp_hal_is_interrupted()) {
         RUN_BACKGROUND_TASKS;
     }
@@ -84,6 +86,7 @@ mp_int_t common_hal_bleio_connection_get_max_packet_length(bleio_connection_inte
 
 void common_hal_bleio_connection_set_connection_interval(bleio_connection_internal_t *self, mp_float_t new_interval) {
     self->conn_params_updating = true;
+    // TODO: Implement this.
 }
 
 mp_obj_tuple_t *common_hal_bleio_connection_discover_remote_services(bleio_connection_obj_t *self, mp_obj_t service_uuids_whitelist) {
@@ -94,6 +97,7 @@ mp_obj_tuple_t *common_hal_bleio_connection_discover_remote_services(bleio_conne
             self->connection->remote_service_list->items);
     mp_obj_list_clear(MP_OBJ_FROM_PTR(self->connection->remote_service_list));
 
+    // TODO: Implement this.
     return services_tuple;
 }
 
diff --git a/ports/espressif/common-hal/_bleio/Descriptor.c b/ports/espressif/common-hal/_bleio/Descriptor.c
index 299fb109ab..016626dbf9 100644
--- a/ports/espressif/common-hal/_bleio/Descriptor.c
+++ b/ports/espressif/common-hal/_bleio/Descriptor.c
@@ -68,10 +68,13 @@ size_t common_hal_bleio_descriptor_get_value(bleio_descriptor_obj_t *self, uint8
         (void)conn_handle;
     }
 
+    // TODO: Implement this.
+
     return 0;
 }
 
 void common_hal_bleio_descriptor_set_value(bleio_descriptor_obj_t *self, mp_buffer_info_t *bufinfo) {
+    // TODO: Implement this.
     // Do GATT operations only if this descriptor has been registered.
     if (self->handle != BLEIO_HANDLE_INVALID) {
         // uint16_t conn_handle = bleio_connection_get_conn_handle(self->characteristic->service->connection);
diff --git a/ports/espressif/common-hal/_bleio/PacketBuffer.c b/ports/espressif/common-hal/_bleio/PacketBuffer.c
index 36f9763c1c..b318ad27d7 100644
--- a/ports/espressif/common-hal/_bleio/PacketBuffer.c
+++ b/ports/espressif/common-hal/_bleio/PacketBuffer.c
@@ -118,7 +118,7 @@ mp_int_t common_hal_bleio_packet_buffer_readinto(bleio_packet_buffer_obj_t *self
     }
 
     // Copy received data. Lock out write interrupt handler while copying.
-
+    // TODO: Implement this.
     return 0;
 }
 
@@ -172,6 +172,7 @@ mp_int_t common_hal_bleio_packet_buffer_write(bleio_packet_buffer_obj_t *self, c
     self->pending_size += len;
     num_bytes_written += len;
 
+    // TODO: Implement this.
 
     // If no writes are queued then sneak in this data.
     if (!self->packet_queued) {
@@ -270,4 +271,5 @@ bool common_hal_bleio_packet_buffer_deinited(bleio_packet_buffer_obj_t *self) {
 void common_hal_bleio_packet_buffer_deinit(bleio_packet_buffer_obj_t *self) {
     if (!common_hal_bleio_packet_buffer_deinited(self)) {
     }
+    // TODO: Implement this.
 }