diff --git a/c/include/libsbp/sbp.h b/c/include/libsbp/sbp.h
index e7eef94d28..25f3888628 100644
--- a/c/include/libsbp/sbp.h
+++ b/c/include/libsbp/sbp.h
@@ -125,6 +125,7 @@ typedef struct {
   u16 frame_len;
   u8 n_read;
   u8 frame_buff[SBP_MAX_FRAME_LEN];
+  u8* msg_buff;
   void* io_context;
   sbp_msg_callbacks_node_t* sbp_msg_callbacks_head;
 } sbp_state_t;
diff --git a/c/src/sbp.c b/c/src/sbp.c
index 9e28b4c47c..2c3aca63cd 100644
--- a/c/src/sbp.c
+++ b/c/src/sbp.c
@@ -325,6 +325,7 @@ void sbp_state_init(sbp_state_t *s)
 
   /* Set the IO context pointer, passed to read and write functions, to NULL. */
   s->io_context = 0;
+  s->msg_buff = SBP_FRAME_MSG_PAYLOAD(s->frame_buff);
 
   /* Clear the callbacks, if any, currently in s */
   sbp_clear_callbacks(s);
diff --git a/c/test/check_sbp.c b/c/test/check_sbp.c
index de40e75edf..2d39ea0287 100644
--- a/c/test/check_sbp.c
+++ b/c/test/check_sbp.c
@@ -814,13 +814,41 @@ START_TEST(test_frame_callbacks)
 }
 END_TEST
 
+START_TEST(test_msg_buff_backwards_compatibility)
+{
+  /* TODO: Tests with different read function behaviour. */
+
+  sbp_state_t s;
+  sbp_state_init(&s);
+  sbp_state_set_io_context(&s, &DUMMY_MEMORY_FOR_IO);
+
+  static sbp_msg_callbacks_node_t n;
+
+  sbp_register_callback(&s, 0x2269, &test_callback, &DUMMY_MEMORY_FOR_CALLBACKS, &n);
+
+  u8 test_data[] = { 0x01, 0x02, 0x03, 0x04 };
+
+  dummy_reset();
+  sbp_send_message(&s, 0x2269, 0x42, sizeof(test_data), test_data, &dummy_write);
+
+  while (dummy_rd < dummy_wr) {
+    fail_unless(sbp_process(&s, &dummy_read) >= SBP_OK,
+        "sbp_process threw an error!");
+  }
+   fail_unless(s.msg_buff[0] == 0x01, "msg_buff backwards compatibility broken!");
+   fail_unless(s.msg_buff[1] == 0x02, "msg_buff backwards compatibility broken!");
+   fail_unless(s.msg_buff[2] == 0x03, "msg_buff backwards compatibility broken!");
+   fail_unless(s.msg_buff[3] == 0x04, "msg_buff backwards compatibility broken!");
+}
+END_TEST
+
 Suite* sbp_suite(void)
 {
   Suite *s = suite_create("SBP");
 
   TCase *tc_core = tcase_create("Core");
 
-
+  tcase_add_test(tc_core, test_msg_buff_backwards_compatibility);
   tcase_add_test(tc_core, test_callbacks);
   tcase_add_test(tc_core, test_sbp_send_message);
   tcase_add_test(tc_core, test_sbp_process);