diff --git a/libs/radio/radio.cpp b/libs/radio/radio.cpp
index c869a747..e362cbdb 100644
--- a/libs/radio/radio.cpp
+++ b/libs/radio/radio.cpp
@@ -41,14 +41,18 @@ namespace radio {
     //% help=radio/received-packet
     Buffer readRawPacket() {
         if (radioEnable() != MICROBIT_OK) return mkBuffer(NULL, 0);
-        packet = uBit.radio.datagram.recv();
-        return mkBuffer(packet.getBytes(), packet.length());
+        uint8_t buf[32];
+        int size = uBit.radio.datagram.recv(buf, sizeof(buf));
+        if (size <= 0)
+            return mkBuffer(NULL, 0);
+        return mkBuffer(buf, size);
     }
 
     /**
      * Sends a raw packet through the radio
      */
     //% advanced=true
+    //% async
     void sendRawPacket(Buffer msg) {
         if (radioEnable() != MICROBIT_OK || NULL == msg) return;
         uBit.radio.datagram.send(msg->data, msg->length);
diff --git a/libs/radio/radio.ts b/libs/radio/radio.ts
index 299b623c..5b2e98b1 100644
--- a/libs/radio/radio.ts
+++ b/libs/radio/radio.ts
@@ -16,10 +16,6 @@ enum RadioPacketProperty {
  */
 //% color=#E3008C weight=96 icon="\uf012"
 namespace radio {
-    export const MAKECODE_RADIO_EVT_NUMBER = 10;
-    export const MAKECODE_RADIO_EVT_STRING = 11;
-    export const MAKECODE_RADIO_EVT_BUFFER = 12;
-    export const MAKECODE_RADIO_EVT_VALUE = 13;
 
     const MAX_FIELD_DOUBLE_NAME_LENGTH = 8;
     const MAX_PAYLOAD_LENGTH = 20;
@@ -51,30 +47,43 @@ namespace radio {
     let initialized = false;
 
     export let lastPacket: RadioPacket;
+    let onReceivedNumberHandler: (receivedNumber: number) => void;
+    let onReceivedValueHandler: (name: string, value: number) => void;
+    let onReceivedStringHandler: (receivedString: string) => void;
+    let onReceivedBufferHandler: (receivedBuffer: Buffer) => void;
 
     function init() {
         if (initialized) return;
         initialized = true;
 
         onDataReceived(() => {
-            lastPacket = RadioPacket.getPacket(readRawPacket());
-            lastPacket.signal = receivedSignalStrength();
+            let buffer: Buffer = readRawPacket();
+            while (buffer && buffer.length) {
+                lastPacket = RadioPacket.getPacket(buffer);
+                lastPacket.signal = receivedSignalStrength();
+                switch (lastPacket.packetType) {
+                    case PACKET_TYPE_NUMBER:
+                    case PACKET_TYPE_DOUBLE:
+                        if (onReceivedNumberHandler)
+                            onReceivedNumberHandler(lastPacket.numberPayload);
+                        break;
+                    case PACKET_TYPE_VALUE:
+                    case PACKET_TYPE_DOUBLE_VALUE:
+                        if (onReceivedValueHandler)
+                            onReceivedValueHandler(lastPacket.stringPayload, lastPacket.numberPayload);
+                        break;
+                    case PACKET_TYPE_BUFFER:
+                        if(onReceivedBufferHandler)
+                            onReceivedBufferHandler(lastPacket.bufferPayload);
+                        break;
+                    case PACKET_TYPE_STRING:
+                        if (onReceivedStringHandler)
+                            onReceivedStringHandler(lastPacket.stringPayload);
+                        break;
+                }
 
-            switch (lastPacket.packetType) {
-                case PACKET_TYPE_NUMBER:
-                case PACKET_TYPE_DOUBLE:
-                    control.raiseEvent(DAL.MICROBIT_ID_RADIO, MAKECODE_RADIO_EVT_NUMBER);
-                    break;
-                case PACKET_TYPE_VALUE:
-                case PACKET_TYPE_DOUBLE_VALUE:
-                    control.raiseEvent(DAL.MICROBIT_ID_RADIO, MAKECODE_RADIO_EVT_VALUE);
-                    break;
-                case PACKET_TYPE_BUFFER:
-                    control.raiseEvent(DAL.MICROBIT_ID_RADIO, MAKECODE_RADIO_EVT_BUFFER);
-                    break;
-                case PACKET_TYPE_STRING:
-                    control.raiseEvent(DAL.MICROBIT_ID_RADIO, MAKECODE_RADIO_EVT_STRING);
-                    break;
+                // read next packet if any
+                buffer = readRawPacket();
             }
         })
     }
@@ -87,9 +96,7 @@ namespace radio {
     //% useLoc="radio.onDataPacketReceived" draggableParameters=reporter
     export function onReceivedNumber(cb: (receivedNumber: number) => void) {
         init();
-        control.onEvent(DAL.MICROBIT_ID_RADIO, MAKECODE_RADIO_EVT_NUMBER, () => {
-            cb(lastPacket.numberPayload);
-        });
+        onReceivedNumberHandler = cb;
     }
 
     /**
@@ -100,9 +107,7 @@ namespace radio {
     //% useLoc="radio.onDataPacketReceived" draggableParameters=reporter
     export function onReceivedValue(cb: (name: string, value: number) => void) {
         init();
-        control.onEvent(DAL.MICROBIT_ID_RADIO, MAKECODE_RADIO_EVT_VALUE, () => {
-            cb(lastPacket.stringPayload, lastPacket.numberPayload);
-        });
+        onReceivedValueHandler = cb;
     }
 
     /**
@@ -113,9 +118,7 @@ namespace radio {
     //% useLoc="radio.onDataPacketReceived" draggableParameters=reporter
     export function onReceivedString(cb: (receivedString: string) => void) {
         init();
-        control.onEvent(DAL.MICROBIT_ID_RADIO, MAKECODE_RADIO_EVT_STRING, () => {
-            cb(lastPacket.stringPayload);
-        });
+        onReceivedStringHandler = cb;
     }
 
     /**
@@ -126,9 +129,7 @@ namespace radio {
     //% useLoc="radio.onDataPacketReceived" draggableParameters=reporter
     export function onReceivedBuffer(cb: (receivedBuffer: Buffer) => void) {
         init();
-        control.onEvent(DAL.MICROBIT_ID_RADIO, MAKECODE_RADIO_EVT_BUFFER, () => {
-            cb(lastPacket.bufferPayload);
-        });
+        onReceivedBufferHandler = cb;
     }
 
     /**
@@ -140,7 +141,7 @@ namespace radio {
     //% blockId=radio_received_packet block="received packet %type=radio_packet_property" blockGap=16
     export function receivedPacket(type: number) {
         if (lastPacket) {
-            switch(type) {
+            switch (type) {
                 case RadioPacketProperty.Time: return lastPacket.time;
                 case RadioPacketProperty.SerialNumber: return lastPacket.serial;
                 case RadioPacketProperty.SignalStrength: return lastPacket.signal;
diff --git a/libs/radio/shims.d.ts b/libs/radio/shims.d.ts
index e30534ab..fbbca79b 100644
--- a/libs/radio/shims.d.ts
+++ b/libs/radio/shims.d.ts
@@ -24,7 +24,8 @@ declare namespace radio {
     /**
      * Sends a raw packet through the radio
      */
-    //% advanced=true shim=radio::sendRawPacket
+    //% advanced=true
+    //% async shim=radio::sendRawPacket
     function sendRawPacket(msg: Buffer): void;
 
     /**
diff --git a/sim/state/radio.ts b/sim/state/radio.ts
index 50fac326..39c9fed6 100644
--- a/sim/state/radio.ts
+++ b/sim/state/radio.ts
@@ -48,7 +48,7 @@ namespace pxsim {
                 rssi: -1,
                 serial: 0,
                 time: 0,
-                payload: { type: -1, groupId: 0 }
+                payload: { type: -1, groupId: 0, bufferData: new Uint8Array(0) }
             };
         }
     }
@@ -109,11 +109,13 @@ namespace pxsim.radio {
     }
 
     export function sendRawPacket(buf: RefBuffer) {
+        let cb = getResume();
         board().radioState.datagram.send({
             type: 0,
             groupId: board().radioState.groupId,
             bufferData: buf.data
         });
+        setTimeout(cb, 1);
     }
 
     export function readRawPacket() {