diff --git a/lib/bluetooth.c b/lib/bluetooth.c
index d7ec72e..ba18ee6 100644
--- a/lib/bluetooth.c
+++ b/lib/bluetooth.c
@@ -258,7 +258,7 @@ int bt_error(uint16_t code)
 	}
 }
 
-char *bt_compidtostr(int compid)
+const char *bt_compidtostr(int compid)
 {
 	switch (compid) {
 	case 0:
diff --git a/lib/bluetooth.h b/lib/bluetooth.h
index 161b7bd..48323f0 100644
--- a/lib/bluetooth.h
+++ b/lib/bluetooth.h
@@ -319,7 +319,7 @@ void *bt_malloc(size_t size);
 void bt_free(void *ptr);
 
 int bt_error(uint16_t code);
-char *bt_compidtostr(int id);
+const char *bt_compidtostr(int id);
 
 typedef struct {
 	uint8_t data[16];