diff --git a/shared/runtime/stdout_helpers.c b/shared/runtime/stdout_helpers.c
index e32aa342e4..6a24cc2eba 100644
--- a/shared/runtime/stdout_helpers.c
+++ b/shared/runtime/stdout_helpers.c
@@ -25,8 +25,6 @@
  */
 
 #include <string.h>
-#include <unistd.h>
-#include "py/mpconfig.h"
 #include "py/mphal.h"
 
 /*
@@ -35,25 +33,26 @@
  * implementation below can be used.
  */
 
-// CIRCUITPY-CHANGE: changes
 // Send "cooked" string of given length, where every occurrence of
-// LF character is replaced with CR LF.
+// LF character is replaced with CR LF ("\n" is converted to "\r\n").
+// This is an optimised version to reduce the number of calls made
+// to mp_hal_stdout_tx_strn.
 void mp_hal_stdout_tx_strn_cooked(const char *str, size_t len) {
-    bool last_cr = false;
-    while (len > 0) {
-        size_t i = 0;
-        if (str[0] == '\n' && !last_cr) {
-            mp_hal_stdout_tx_strn("\r", 1);
-            i = 1;
+    const char *last = str;
+    while (len--) {
+        if (*str == '\n') {
+            if (str > last) {
+                mp_hal_stdout_tx_strn(last, str - last);
+            }
+            mp_hal_stdout_tx_strn("\r\n", 2);
+            ++str;
+            last = str;
+        } else {
+            ++str;
         }
-        // Lump all characters on the next line together.
-        while ((last_cr || str[i] != '\n') && i < len) {
-            last_cr = str[i] == '\r';
-            i++;
-        }
-        mp_hal_stdout_tx_strn(str, i);
-        str = &str[i];
-        len -= i;
+    }
+    if (str > last) {
+        mp_hal_stdout_tx_strn(last, str - last);
     }
 }