Index: uspace/lib/usb/src/request.c
===================================================================
--- uspace/lib/usb/src/request.c	(revision d493ac1796e11430f9f5fb207fcc9f797d4c2a54)
+++ uspace/lib/usb/src/request.c	(revision 37b4794eabdeb439955f8c2b23ff09def7c98842)
@@ -502,5 +502,6 @@
  *
  * @param[in] pipe Control endpoint pipe (session must be already started).
- * @param[in] index String index (in native endianess).
+ * @param[in] index String index (in native endianess),
+ *	first index has number 1 (index from descriptors can be used directly).
  * @param[in] lang String language (in native endianess).
  * @param[out] string_ptr Where to store allocated string in native encoding.
@@ -513,6 +514,9 @@
 		return EBADMEM;
 	}
-	/* Index is actually one byte value. */
-	if (index > 0xFF) {
+	/*
+	 * Index is actually one byte value and zero index is used
+	 * to retrieve list of supported languages.
+	 */
+	if ((index < 1) || (index > 0xFF)) {
 		return ERANGE;
 	}