diff --git a/src/platforms/common/usb_serial.c b/src/platforms/common/usb_serial.c
index e33e290..c64c8a0 100644
--- a/src/platforms/common/usb_serial.c
+++ b/src/platforms/common/usb_serial.c
@@ -212,4 +212,81 @@ size_t usbuart_debug_write(const char *buf, const size_t len)
 
 	return len;
 }
+
+/*
+ * newlib defines _write as a weak link'd function for user code to override.
+ *
+ * This function forms the root of the implementation of a variety of functions
+ * that can write to stdout/stderr, including printf().
+ *
+ * The result of this function is the number of bytes written.
+ */
+/* NOLINTNEXTLINE(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp) */
+int _write(const int file, const void *const ptr, const size_t len)
+{
+	(void)file;
+#ifdef PLATFORM_HAS_DEBUG
+	if (debug_bmp)
+		return usbuart_debug_write(ptr, len);
+#endif
+	return len;
+}
+
+/*
+ * newlib defines isatty as a weak link'd function for user code to override.
+ *
+ * The result of this function is always 'true'.
+ */
+int isatty(const int file)
+{
+	(void)file;
+	return true;
+}
+
+enum {
+	RDI_SYS_OPEN = 0x01,
+};
+
+typedef struct ex_frame {
+	uint32_t r0;
+	const uint32_t *params;
+	uint32_t r2;
+	uint32_t r3;
+	uint32_t r12;
+	uintptr_t lr;
+	uintptr_t return_address;
+} ex_frame_s;
+
+void debug_monitor_handler(void) __attribute__((used)) __attribute__((naked));
+
+/*
+ * This implements the other half of the newlib syscall puzzle.
+ * When newlib is built for ARM, various calls that do file IO
+ * such as printf end up calling [_swiwrite](https://github.com/mirror/newlib-cygwin/blob/master/newlib/libc/sys/arm/syscalls.c#L317)
+ * and other similar low-level implementation functions. These
+ * generate `swi` instructions for the "RDI Monitor" and that lands us.. here.
+ *
+ * The RDI calling convention sticks the file number in r0, the buffer pointer in r1, and length in r2.
+ * ARMv7-M's SWI (SVC) instruction then takes all that and maps it into an exception frame on the stack.
+ */
+void debug_monitor_handler(void)
+{
+	ex_frame_s *frame;
+	__asm__(
+		"mov %[frame], sp" :
+		[frame] "=r" (frame)
+	);
+
+	/* Make sure to return to the instruction after the SWI/BKPT */
+	frame->return_address += 2U;
+
+	switch (frame->r0) {
+	case RDI_SYS_OPEN:
+		frame->r0 = 1;
+		break;
+	default:
+		frame->r0 = UINT32_MAX;
+	}
+	__asm__("bx lr");
+}
 #endif
diff --git a/src/platforms/stm32/usbuart.c b/src/platforms/stm32/usbuart.c
index 668cce5..794d44e 100644
--- a/src/platforms/stm32/usbuart.c
+++ b/src/platforms/stm32/usbuart.c
@@ -492,82 +492,3 @@ void USBUSART_DMA_RXTX_ISR(void)
 		USBUSART_DMA_TX_ISR();
 }
 #endif
-
-#ifdef ENABLE_DEBUG
-/*
- * newlib defines _write as a weak link'd function for user code to override.
- *
- * This function forms the root of the implementation of a variety of functions
- * that can write to stdout/stderr, including printf().
- *
- * The result of this function is the number of bytes written.
- */
-/* NOLINTNEXTLINE(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp) */
-int _write(const int file, const void *const ptr, const size_t len)
-{
-	(void)file;
-#ifdef PLATFORM_HAS_DEBUG
-	if (debug_bmp)
-		return usbuart_debug_write(ptr, len);
-#endif
-	return len;
-}
-
-/*
- * newlib defines isatty as a weak link'd function for user code to override.
- *
- * The result of this function is always 'true'.
- */
-int isatty(const int file)
-{
-	(void)file;
-	return true;
-}
-
-enum {
-	RDI_SYS_OPEN = 0x01,
-};
-
-typedef struct ex_frame {
-	uint32_t r0;
-	const uint32_t *params;
-	uint32_t r2;
-	uint32_t r3;
-	uint32_t r12;
-	uintptr_t lr;
-	uintptr_t return_address;
-} ex_frame_s;
-
-void debug_monitor_handler(void) __attribute__((used)) __attribute__((naked));
-
-/*
- * This implements the other half of the newlib syscall puzzle.
- * When newlib is built for ARM, various calls that do file IO
- * such as printf end up calling [_swiwrite](https://github.com/mirror/newlib-cygwin/blob/master/newlib/libc/sys/arm/syscalls.c#L317)
- * and other similar low-level implementation functions. These
- * generate `swi` instructions for the "RDI Monitor" and that lands us.. here.
- *
- * The RDI calling convention sticks the file number in r0, the buffer pointer in r1, and length in r2.
- * ARMv7-M's SWI (SVC) instruction then takes all that and maps it into an exception frame on the stack.
- */
-void debug_monitor_handler(void)
-{
-	ex_frame_s *frame;
-	__asm__(
-		"mov %[frame], sp" :
-		[frame] "=r" (frame)
-	);
-
-	/* Make sure to return to the instruction after the SWI/BKPT */
-	frame->return_address += 2U;
-
-	switch (frame->r0) {
-	case RDI_SYS_OPEN:
-		frame->r0 = 1;
-		break;
-	default:
-		frame->r0 = UINT32_MAX;
-	}
-	__asm__("bx lr");
-}
-#endif