diff --git a/src/portable/raspberrypi/rp2040/dcd_rp2040.c b/src/portable/raspberrypi/rp2040/dcd_rp2040.c
index 4952d29b1..33edf0f1e 100644
--- a/src/portable/raspberrypi/rp2040/dcd_rp2040.c
+++ b/src/portable/raspberrypi/rp2040/dcd_rp2040.c
@@ -46,9 +46,6 @@
 /* Low level controller
  *------------------------------------------------------------------*/
 
-#define usb_hw_set hw_set_alias(usb_hw)
-#define usb_hw_clear hw_clear_alias(usb_hw)
-
 // Init these in dcd_init
 static uint8_t *next_buffer_ptr;
 
diff --git a/src/portable/raspberrypi/rp2040/hcd_rp2040.c b/src/portable/raspberrypi/rp2040/hcd_rp2040.c
index 9e6bdad44..28abd7939 100644
--- a/src/portable/raspberrypi/rp2040/hcd_rp2040.c
+++ b/src/portable/raspberrypi/rp2040/hcd_rp2040.c
@@ -56,9 +56,6 @@ static_assert(PICO_USB_HOST_INTERRUPT_ENDPOINTS <= USB_MAX_ENDPOINTS, "");
 static struct hw_endpoint ep_pool[1 + PICO_USB_HOST_INTERRUPT_ENDPOINTS];
 #define epx (ep_pool[0])
 
-#define usb_hw_set   hw_set_alias(usb_hw)
-#define usb_hw_clear hw_clear_alias(usb_hw)
-
 // Flags we set by default in sie_ctrl (we add other bits on top)
 enum {
   SIE_CTRL_BASE = USB_SIE_CTRL_SOF_EN_BITS      | USB_SIE_CTRL_KEEP_ALIVE_EN_BITS |
diff --git a/src/portable/raspberrypi/rp2040/rp2040_usb.c b/src/portable/raspberrypi/rp2040/rp2040_usb.c
index 5c7645902..77d5f2f8f 100644
--- a/src/portable/raspberrypi/rp2040/rp2040_usb.c
+++ b/src/portable/raspberrypi/rp2040/rp2040_usb.c
@@ -38,14 +38,11 @@ const char *ep_dir_string[] = {
         "in",
 };
 
-TU_ATTR_ALWAYS_INLINE static inline void _hw_endpoint_lock_update(__unused struct hw_endpoint * ep, __unused int delta) {
-    // todo add critsec as necessary to prevent issues between worker and IRQ...
-    //  note that this is perhaps as simple as disabling IRQs because it would make
-    //  sense to have worker and IRQ on same core, however I think using critsec is about equivalent.
-}
+#if TUD_OPT_RP2040_USB_DEVICE_UFRAME_FIX
+volatile uint32_t last_sof = 0;
+#endif
 
 static void _hw_endpoint_xfer_sync(struct hw_endpoint *ep);
-static void _hw_endpoint_start_next_buffer(struct hw_endpoint *ep);
 
 // if usb hardware is in host mode
 TU_ATTR_ALWAYS_INLINE static inline bool is_host_mode(void)
@@ -157,7 +154,7 @@ static uint32_t __tusb_irq_path_func(prepare_ep_buffer)(struct hw_endpoint *ep,
 }
 
 // Prepare buffer control register value
-static void __tusb_irq_path_func(_hw_endpoint_start_next_buffer)(struct hw_endpoint *ep)
+void __tusb_irq_path_func(hw_endpoint_start_next_buffer)(struct hw_endpoint *ep)
 {
   uint32_t ep_ctrl = *ep->endpoint_control;
 
@@ -201,7 +198,7 @@ static void __tusb_irq_path_func(_hw_endpoint_start_next_buffer)(struct hw_endpo
 
 void hw_endpoint_xfer_start(struct hw_endpoint *ep, uint8_t *buffer, uint16_t total_len)
 {
-  _hw_endpoint_lock_update(ep, 1);
+  hw_endpoint_lock_update(ep, 1);
 
   if ( ep->active )
   {
@@ -218,8 +215,8 @@ void hw_endpoint_xfer_start(struct hw_endpoint *ep, uint8_t *buffer, uint16_t to
   ep->active        = true;
   ep->user_buf      = buffer;
 
-  _hw_endpoint_start_next_buffer(ep);
-  _hw_endpoint_lock_update(ep, -1);
+  hw_endpoint_start_next_buffer(ep);
+  hw_endpoint_lock_update(ep, -1);
 }
 
 // sync endpoint buffer and return transferred bytes
@@ -312,7 +309,7 @@ static void __tusb_irq_path_func(_hw_endpoint_xfer_sync) (struct hw_endpoint *ep
 // Returns true if transfer is complete
 bool __tusb_irq_path_func(hw_endpoint_xfer_continue)(struct hw_endpoint *ep)
 {
-  _hw_endpoint_lock_update(ep, 1);
+  hw_endpoint_lock_update(ep, 1);
   // Part way through a transfer
   if (!ep->active)
   {
@@ -329,15 +326,15 @@ bool __tusb_irq_path_func(hw_endpoint_xfer_continue)(struct hw_endpoint *ep)
     pico_trace("Completed transfer of %d bytes on ep %d %s\n",
                ep->xferred_len, tu_edpt_number(ep->ep_addr), ep_dir_string[tu_edpt_dir(ep->ep_addr)]);
     // Notify caller we are done so it can notify the tinyusb stack
-    _hw_endpoint_lock_update(ep, -1);
+    hw_endpoint_lock_update(ep, -1);
     return true;
   }
   else
   {
-    _hw_endpoint_start_next_buffer(ep);
+    hw_endpoint_start_next_buffer(ep);
   }
 
-  _hw_endpoint_lock_update(ep, -1);
+  hw_endpoint_lock_update(ep, -1);
   // More work to do
   return false;
 }
diff --git a/src/portable/raspberrypi/rp2040/rp2040_usb.h b/src/portable/raspberrypi/rp2040/rp2040_usb.h
index b65d32fd4..be1f1e5ec 100644
--- a/src/portable/raspberrypi/rp2040/rp2040_usb.h
+++ b/src/portable/raspberrypi/rp2040/rp2040_usb.h
@@ -26,6 +26,9 @@
 #define __tusb_irq_path_func(x) x
 #endif
 
+#define usb_hw_set hw_set_alias(usb_hw)
+#define usb_hw_clear hw_clear_alias(usb_hw)
+
 #define pico_info(...)  TU_LOG(2, __VA_ARGS__)
 #define pico_trace(...) TU_LOG(3, __VA_ARGS__)
 
@@ -79,6 +82,13 @@ void rp2040_usb_init(void);
 void hw_endpoint_xfer_start(struct hw_endpoint *ep, uint8_t *buffer, uint16_t total_len);
 bool hw_endpoint_xfer_continue(struct hw_endpoint *ep);
 void hw_endpoint_reset_transfer(struct hw_endpoint *ep);
+void hw_endpoint_start_next_buffer(struct hw_endpoint *ep);
+
+TU_ATTR_ALWAYS_INLINE static inline void hw_endpoint_lock_update(__unused struct hw_endpoint * ep, __unused int delta) {
+  // todo add critsec as necessary to prevent issues between worker and IRQ...
+  //  note that this is perhaps as simple as disabling IRQs because it would make
+  //  sense to have worker and IRQ on same core, however I think using critsec is about equivalent.
+}
 
 void _hw_endpoint_buffer_control_update32(struct hw_endpoint *ep, uint32_t and_mask, uint32_t or_mask);