diff --git a/sys/fmt/fmt.c b/sys/fmt/fmt.c
index 74fb79c016..19955416dc 100644
--- a/sys/fmt/fmt.c
+++ b/sys/fmt/fmt.c
@@ -21,15 +21,9 @@
 #include <assert.h>
 #include <stdarg.h>
 #include <stdint.h>
-#include <unistd.h>
+#include <stdio.h>
 #include <string.h>
-
-#if defined(__WITH_AVRLIBC__) || defined(__mips__)
-#include <stdio.h>  /* for fwrite() */
-#else
-/* work around broken sys/posix/unistd.h */
-ssize_t write(int fildes, const void *buf, size_t nbyte);
-#endif
+#include <unistd.h>
 
 #include "kernel_defines.h"
 #include "fmt.h"
@@ -505,19 +499,28 @@ uint32_t scn_u32_hex(const char *str, size_t n)
 
 void print(const char *s, size_t n)
 {
-#ifdef __WITH_AVRLIBC__
-    /* AVR's libc doesn't offer write(), so use fwrite() instead */
-    fwrite(s, n, 1, stdout);
-#else
     while (n > 0) {
-        ssize_t written = write(STDOUT_FILENO, s, n);
+        ssize_t written;
+        if (IS_USED(MODULE_STDIO_NATIVE)) {
+            /* for native fwrite is not wrapped and would use the system's
+             * write directly, resulting in corrupted output. Instead, use the
+             * stdio_write wrapper directly here to force all output from
+             * puts() / printf() and fmt to be handled the same. */
+            extern ssize_t stdio_write(const void* buffer, size_t len);
+            written = stdio_write(s, n);
+        }
+        else {
+            /* For all but native: Use fwrite rather than the cheaper unbuffered
+             * write() to avoid corrupted output when mixing stdio and fmt
+             * for C libs that use buffered output */
+            written = fwrite(s, 1, n, stdout);
+        }
         if (written < 0) {
             break;
         }
         n -= written;
         s += written;
     }
-#endif /* __WITH_AVRLIBC__ */
 }
 
 void print_u32_dec(uint32_t val)