diff --git a/py/ringbuf.c b/py/ringbuf.c
index a904a37413..a720abc7d7 100644
--- a/py/ringbuf.c
+++ b/py/ringbuf.c
@@ -27,11 +27,20 @@
 
 #include "ringbuf.h"
 
+bool ringbuf_init(ringbuf_t *r, uint8_t *buf, size_t capacity) {
+    r->heap = false;
+    r->buf = buf;
+    r->size = capacity + 1;
+    r->iget = r->iput = 0;
+    return r->buf != NULL;
+}
+
 // Dynamic initialization. This should be accessible from a root pointer.
 // capacity is the number of bytes the ring buffer can hold. The actual
 // size of the buffer is one greater than that, due to how the buffer
 // handles empty and full statuses.
 bool ringbuf_alloc(ringbuf_t *r, size_t capacity, bool long_lived) {
+    r->heap = true;
     r->buf = gc_alloc(capacity + 1, false, long_lived);
     r->size = capacity + 1;
     r->iget = r->iput = 0;
@@ -39,7 +48,10 @@ bool ringbuf_alloc(ringbuf_t *r, size_t capacity, bool long_lived) {
 }
 
 void ringbuf_free(ringbuf_t *r) {
-    gc_free(r->buf);
+    if (r->heap) {
+        gc_free(r->buf);
+    }
+    r->buf = (uint8_t *)NULL;
     r->size = 0;
     ringbuf_clear(r);
 }
diff --git a/py/ringbuf.h b/py/ringbuf.h
index 35550d7750..6ed72dcf1a 100644
--- a/py/ringbuf.h
+++ b/py/ringbuf.h
@@ -37,14 +37,13 @@ typedef struct _ringbuf_t {
     uint32_t size;
     uint32_t iget;
     uint32_t iput;
+    bool heap;
 } ringbuf_t;
 
 // Note that the capacity of the buffer is N-1!
 
-// Static initialization:
-// byte buf_array[N];
-// ringbuf_t buf = {buf_array, sizeof(buf_array)};
-
+// For static initialization use ringbuf_init()
+bool ringbuf_init(ringbuf_t *r, uint8_t *buf, size_t capacity);
 bool ringbuf_alloc(ringbuf_t *r, size_t capacity, bool long_lived);
 void ringbuf_free(ringbuf_t *r);
 size_t ringbuf_capacity(ringbuf_t *r);