diff --git a/platform/posix/hci_transport_h5_posix.c b/platform/posix/hci_transport_h5_posix.c
index b6dc0e18d..a841bddc9 100644
--- a/platform/posix/hci_transport_h5_posix.c
+++ b/platform/posix/hci_transport_h5_posix.c
@@ -599,9 +599,7 @@ static int hci_transport_h5_close(void){
     return 0;
 }
 
-static void hci_transport_h5_process(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type) {
-    if (hci_transport_h5_data_source.fd < 0) return;
-
+static void hci_transport_h5_process_read(btstack_data_source_t *ds) {
     // process data byte by byte
     uint8_t data;
     while (1) {
@@ -617,6 +615,23 @@ static void hci_transport_h5_process(btstack_data_source_t *ds, btstack_data_sou
     };
 }
 
+static void hci_transport_h5_process_write(btstack_data_source_t *ds) {
+}
+
+static void hci_transport_h5_process(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type) {
+    if (hci_transport_h5_data_source.fd < 0) return;
+    switch (callback_type){
+        case DATA_SOURCE_CALLBACK_READ:
+            hci_transport_h5_process_read(ds);
+            break;
+        case DATA_SOURCE_CALLBACK_WRITE:
+            hci_transport_h5_process_write(ds);
+            break;
+        default:
+            break;
+    }
+}
+
 // get h5 singleton
 const hci_transport_t * hci_transport_h5_instance(void) {
     if (hci_transport_h5 == NULL) {