diff --git a/inc/bluetooth/MicroBitPartialFlashingService.h b/inc/bluetooth/MicroBitPartialFlashingService.h
index 64a1d5bb..198b1cb3 100644
--- a/inc/bluetooth/MicroBitPartialFlashingService.h
+++ b/inc/bluetooth/MicroBitPartialFlashingService.h
@@ -101,7 +101,8 @@ class MicroBitPartialFlashingService
     uint8_t blockPacketCount = 0;
 
     // Keep track of blocks of data
-    uint32_t block[16];
+    // uint32_t block[16]; // Replaced with pointer, memory allocated when PFS is used
+    uint32_t *block = NULL;
     uint8_t  blockNum = 0;
     uint32_t offset   = 0;
 
diff --git a/source/bluetooth/MicroBitPartialFlashingService.cpp b/source/bluetooth/MicroBitPartialFlashingService.cpp
index b0f1c42a..d1480831 100644
--- a/source/bluetooth/MicroBitPartialFlashingService.cpp
+++ b/source/bluetooth/MicroBitPartialFlashingService.cpp
@@ -41,6 +41,7 @@ DEALINGS IN THE SOFTWARE.
 MicroBitPartialFlashingService::MicroBitPartialFlashingService(BLEDevice &_ble, EventModel &_messageBus) :
         ble(_ble), messageBus(_messageBus)
 {
+
     // Set up partial flashing characteristic
     uint8_t initCharacteristicValue = 0x00;
     GattCharacteristic partialFlashCharacteristic(MicroBitPartialFlashingServiceCharacteristicUUID, &initCharacteristicValue, sizeof(initCharacteristicValue),
@@ -48,7 +49,6 @@ MicroBitPartialFlashingService::MicroBitPartialFlashingService(BLEDevice &_ble,
 
     // Set default security requirements
     partialFlashCharacteristic.requireSecurity(SecurityManager::MICROBIT_BLE_SECURITY_LEVEL);
-
     // Create Partial Flashing Service
     GattCharacteristic *characteristics[] = {&partialFlashCharacteristic};
     GattService         service(MicroBitPartialFlashingServiceUUID, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic*) );
@@ -200,6 +200,11 @@ void MicroBitPartialFlashingService::flashData(uint8_t *data)
 
         packetCount++;
 
+        // Reallocate block
+        if(block == NULL) {
+            (uint32_t*) malloc(16 * sizeof(uint32_t));
+        }
+
         // Add to block
         memcpy(block + (4*blockNum), data + 4, 16);