diff --git a/radio/src/audio_arm.cpp b/radio/src/audio_arm.cpp
index bb056b5a1..ceb46c521 100644
--- a/radio/src/audio_arm.cpp
+++ b/radio/src/audio_arm.cpp
@@ -336,12 +336,14 @@ void getLogicalSwitchAudioFile(char * filename, int index, unsigned int event)
 
 #if defined(PCBTARANIS)
   *str++ = 'L';
-  if (index >= 10) {
-    div_t qr = div(index, 10);
+  if (index >= 9) {
+    div_t qr = div(index+1, 10);
     *str++ = '1' + qr.quot;
-    index = qr.rem;
+    *str++ = '0' + qr.rem;
+  }
+  else {
+    *str++ = '1' + index;
   }
-  *str++ = '1' + index;
 #else
   int len = STR_VSWITCHES[0];
   strncpy(str, &STR_VSWITCHES[1+len*(index+SWSRC_FIRST_LOGICAL_SWITCH)], len);