diff --git a/py/malloc.c b/py/malloc.c
index 818a3e57a9..6835ed7c99 100644
--- a/py/malloc.c
+++ b/py/malloc.c
@@ -147,7 +147,11 @@ void *m_realloc(void *ptr, size_t new_num_bytes) {
     MP_STATE_MEM(current_bytes_allocated) += diff;
     UPDATE_PEAK();
 #endif
+    #if MICROPY_MALLOC_USES_ALLOCATED_SIZE
     DEBUG_printf("realloc %p, %d, %d : %p\n", ptr, old_num_bytes, new_num_bytes, new_ptr);
+    #else
+    DEBUG_printf("realloc %p, %d : %p\n", ptr, new_num_bytes, new_ptr);
+    #endif
     return new_ptr;
 }
 
@@ -171,7 +175,11 @@ void *m_realloc_maybe(void *ptr, size_t new_num_bytes, bool allow_move) {
         UPDATE_PEAK();
     }
 #endif
+    #if MICROPY_MALLOC_USES_ALLOCATED_SIZE
     DEBUG_printf("realloc %p, %d, %d : %p\n", ptr, old_num_bytes, new_num_bytes, new_ptr);
+    #else
+    DEBUG_printf("realloc %p, %d, %d : %p\n", ptr, new_num_bytes, new_ptr);
+    #endif
     return new_ptr;
 }
 
@@ -184,7 +192,11 @@ void m_free(void *ptr) {
 #if MICROPY_MEM_STATS
     MP_STATE_MEM(current_bytes_allocated) -= num_bytes;
 #endif
+    #if MICROPY_MALLOC_USES_ALLOCATED_SIZE
     DEBUG_printf("free %p, %d\n", ptr, num_bytes);
+    #else
+    DEBUG_printf("free %p\n", ptr);
+    #endif
 }
 
 #if MICROPY_MEM_STATS