diff --git a/src/common/tusb_fifo.h b/src/common/tusb_fifo.h
index 0276c8044..62ee942d2 100644
--- a/src/common/tusb_fifo.h
+++ b/src/common/tusb_fifo.h
@@ -109,7 +109,7 @@ static inline void tu_fifo_config_mutex(tu_fifo_t *f, tu_fifo_mutex_t write_mute
 
 bool     tu_fifo_write                  (tu_fifo_t* f, void const * p_data);
 uint16_t tu_fifo_write_n                (tu_fifo_t* f, void const * p_data, uint16_t n);
-uint16_t tu_fifo_write_n_const_addr              (tu_fifo_t* f, const void * data, uint16_t n);
+uint16_t tu_fifo_write_n_const_addr     (tu_fifo_t* f, const void * data, uint16_t n);
 
 bool     tu_fifo_read                   (tu_fifo_t* f, void * p_buffer);
 uint16_t tu_fifo_read_n                 (tu_fifo_t* f, void * p_buffer, uint16_t n);
diff --git a/src/device/dcd.h b/src/device/dcd.h
index 89f8760d0..1e5b3ff1e 100644
--- a/src/device/dcd.h
+++ b/src/device/dcd.h
@@ -134,8 +134,9 @@ void dcd_edpt_close           (uint8_t rhport, uint8_t ep_addr) TU_ATTR_WEAK;
 // Submit a transfer, When complete dcd_event_xfer_complete() is invoked to notify the stack
 bool dcd_edpt_xfer            (uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes);
 
-// Submit an ISO transfer, When complete dcd_event_xfer_complete() is invoked to notify the stack
-bool dcd_edpt_xfer_fifo (uint8_t rhport, uint8_t ep_addr, tu_fifo_t * ff, uint16_t total_bytes);
+// Submit an transfer using fifo, When complete dcd_event_xfer_complete() is invoked to notify the stack
+// This API is optional, may be useful for register-based for transferring data.
+bool dcd_edpt_xfer_fifo       (uint8_t rhport, uint8_t ep_addr, tu_fifo_t * ff, uint16_t total_bytes) TU_ATTR_WEAK;
 
 // Stall endpoint
 void dcd_edpt_stall           (uint8_t rhport, uint8_t ep_addr);
diff --git a/src/osal/osal_pico.h b/src/osal/osal_pico.h
index c277af271..bae1217eb 100644
--- a/src/osal/osal_pico.h
+++ b/src/osal/osal_pico.h
@@ -143,7 +143,7 @@ static inline bool osal_queue_receive(osal_queue_t qhdl, void* data)
   // TODO: revisit... docs say that mutexes are never used from IRQ context,
   //  however osal_queue_recieve may be. therefore my assumption is that
   //  the fifo mutex is not populated for queues used from an IRQ context
-  assert(!qhdl->ff.mutex);
+  //assert(!qhdl->ff.mutex);
 
   _osal_q_lock(qhdl);
   bool success = tu_fifo_read(&qhdl->ff, data);
@@ -157,7 +157,7 @@ static inline bool osal_queue_send(osal_queue_t qhdl, void const * data, bool in
   // TODO: revisit... docs say that mutexes are never used from IRQ context,
   //  however osal_queue_recieve may be. therefore my assumption is that
   //  the fifo mutex is not populated for queues used from an IRQ context
-  assert(!qhdl->ff.mutex);
+  //assert(!qhdl->ff.mutex);
 
   _osal_q_lock(qhdl);
   bool success = tu_fifo_write(&qhdl->ff, data);
diff --git a/src/portable/raspberrypi/rp2040/dcd_rp2040.c b/src/portable/raspberrypi/rp2040/dcd_rp2040.c
index f844a0c65..7731078b5 100644
--- a/src/portable/raspberrypi/rp2040/dcd_rp2040.c
+++ b/src/portable/raspberrypi/rp2040/dcd_rp2040.c
@@ -35,7 +35,8 @@
 #include "pico/fix/rp2040_usb_device_enumeration.h"
 #endif
 
-
+#include "osal/osal.h"
+#include "common/tusb_fifo.h"
 #include "device/dcd.h"
 
 /*------------------------------------------------------------------*/