diff --git a/opencom_xl_firmware.ino b/opencom_xl_firmware.ino
index 6931983..c4abe47 100644
--- a/opencom_xl_firmware.ino
+++ b/opencom_xl_firmware.ino
@@ -66,6 +66,7 @@ volatile uint16_t queued_bytes[INTERFACE_COUNT] = {0};
 volatile uint16_t queue_cursor[INTERFACE_COUNT] = {0};
 volatile uint16_t current_packet_start[INTERFACE_COUNT] = {0};
 volatile bool serial_buffering = false;
+extern void setup_interfaces(); // from src/misc/ModemISR.h
 #if HAS_BLUETOOTH || HAS_BLE == true
   bool bt_init_ran = false;
 #endif
@@ -174,6 +175,8 @@ void setup() {
   memset(seq, 0xFF, sizeof(seq));
   memset(read_len, 0, sizeof(read_len));
 
+  setup_interfaces();
+
   modem_packet_queue = xQueueCreate(MODEM_QUEUE_SIZE, sizeof(modem_packet_t*));
 
   for (int i = 0; i < INTERFACE_COUNT; i++) {