diff --git a/src/ersky9x/audio.cpp b/src/ersky9x/audio.cpp
index 057bbc34d..86d575fa8 100644
--- a/src/ersky9x/audio.cpp
+++ b/src/ersky9x/audio.cpp
@@ -619,9 +619,9 @@ void audioEvent(uint8_t e, uint8_t f)
 
 void pushPrompt(uint16_t prompt)
 {
-  char filename[] = SYSTEM_SOUNDS_PATH "/0000.wav";
+  char filename[] = SYSTEM_SOUNDS_PATH "/0000" SOUNDS_EXT;
 
-  for (int8_t i=3; i>=0; i++) {
+  for (int8_t i=3; i>=0; i--) {
     filename[sizeof(SYSTEM_SOUNDS_PATH)+i] = '0' + (prompt%10);
     prompt /= 10;
   }