diff --git a/extmod/nimble/modbluetooth_nimble.c b/extmod/nimble/modbluetooth_nimble.c
index bbff26b535..e4a048e3d3 100644
--- a/extmod/nimble/modbluetooth_nimble.c
+++ b/extmod/nimble/modbluetooth_nimble.c
@@ -608,7 +608,9 @@ static int characteristic_access_cb(uint16_t conn_handle, uint16_t value_handle,
                 return BLE_ATT_ERR_ATTR_NOT_FOUND;
             }
 
-            os_mbuf_append(ctxt->om, entry->data, entry->data_len);
+            if (os_mbuf_append(ctxt->om, entry->data, entry->data_len)) {
+                return BLE_ATT_ERR_INSUFFICIENT_RES;
+            }
 
             return 0;
         case BLE_GATT_ACCESS_OP_WRITE_CHR:
@@ -625,6 +627,8 @@ static int characteristic_access_cb(uint16_t conn_handle, uint16_t value_handle,
             entry->data_len = MIN(entry->data_alloc, OS_MBUF_PKTLEN(ctxt->om) + offset);
             os_mbuf_copydata(ctxt->om, 0, entry->data_len - offset, entry->data + offset);
 
+            // TODO: Consider failing with BLE_ATT_ERR_INSUFFICIENT_RES if the buffer is full.
+
             mp_bluetooth_gatts_on_write(conn_handle, value_handle);
 
             return 0;