diff --git a/src/platforms/common/usb_serial.c b/src/platforms/common/usb_serial.c
index 024678e..e33e290 100644
--- a/src/platforms/common/usb_serial.c
+++ b/src/platforms/common/usb_serial.c
@@ -48,6 +48,7 @@
 #endif
 #include "usbuart.h"
 
+#include <libopencm3/cm3/cortex.h>
 #include <libopencm3/cm3/nvic.h>
 #include <libopencm3/usb/cdc.h>
 
@@ -184,3 +185,31 @@ void debug_uart_send_stdout(const uint8_t *const data, const size_t len)
 		nvic_enable_irq(USB_IRQ);
 	}
 }
+
+#ifdef ENABLE_DEBUG
+size_t usbuart_debug_write(const char *buf, const size_t len)
+{
+	if (nvic_get_active_irq(USB_IRQ) || nvic_get_active_irq(USBUSART_IRQ) || nvic_get_active_irq(USBUSART_DMA_RX_IRQ))
+		return 0;
+
+	CM_ATOMIC_CONTEXT();
+
+	for (size_t i = 0; i < len && (usb_dbg_in + 1) % RX_FIFO_SIZE != usb_dbg_out; ++i)
+	{
+		if (buf[i] == '\n')
+		{
+			usb_dbg_buf[usb_dbg_in++] = '\r';
+			usb_dbg_in %= RX_FIFO_SIZE;
+
+			if ((usb_dbg_in + 1) % RX_FIFO_SIZE == usb_dbg_out)
+				break;
+		}
+		usb_dbg_buf[usb_dbg_in++] = buf[i];
+		usb_dbg_in %= RX_FIFO_SIZE;
+	}
+
+	usbuart_run();
+
+	return len;
+}
+#endif
diff --git a/src/platforms/stm32/usbuart.c b/src/platforms/stm32/usbuart.c
index 1c32fd4..668cce5 100644
--- a/src/platforms/stm32/usbuart.c
+++ b/src/platforms/stm32/usbuart.c
@@ -260,34 +260,6 @@ void usbuart_usb_out_cb(usbd_device *dev, uint8_t ep)
 }
 #endif
 
-#ifdef USBUART_DEBUG
-size_t usbuart_debug_write(const char *buf, const size_t len)
-{
-	if (nvic_get_active_irq(USB_IRQ) || nvic_get_active_irq(USBUSART_IRQ) || nvic_get_active_irq(USBUSART_DMA_RX_IRQ))
-		return 0;
-
-	CM_ATOMIC_CONTEXT();
-
-	for (size_t i = 0; i < len && (usb_dbg_in + 1) % RX_FIFO_SIZE != usb_dbg_out; i++)
-	{
-		if (buf[i] == '\n')
-		{
-			usb_dbg_buf[usb_dbg_in++] = '\r';
-			usb_dbg_in %= RX_FIFO_SIZE;
-
-			if ((usb_dbg_in + 1) % RX_FIFO_SIZE == usb_dbg_out)
-				break;
-		}
-		usb_dbg_buf[usb_dbg_in++] = buf[i];
-		usb_dbg_in %= RX_FIFO_SIZE;
-	}
-
-	usbuart_run();
-
-	return len;
-}
-#endif
-
 /*
  * Runs deferred processing for USBUSART RX, draining RX FIFO by sending
  * characters to host PC via CDCACM. Allowed to write to FIFO OUT pointer.