diff --git a/program/lib/Roundcube/rcube_charset.php b/program/lib/Roundcube/rcube_charset.php
index 88eb6001f..5ef78b886 100644
--- a/program/lib/Roundcube/rcube_charset.php
+++ b/program/lib/Roundcube/rcube_charset.php
@@ -307,7 +307,7 @@ class rcube_charset
 
         // convert charset using iconv module
         if ($iconv_options !== false && $from != 'UTF7-IMAP' && $to != 'UTF7-IMAP'
-            && $from !== 'ISO-2022-JP'
+            && $from !== 'ISO-2022-JP' && $to !== 'ISO-2022-JP'
         ) {
             // throw an exception if iconv reports an illegal character in input
             // it means that input string has been truncated
diff --git a/tests/Framework/Charset.php b/tests/Framework/Charset.php
index f36b7b969..85cb4ba6c 100644
--- a/tests/Framework/Charset.php
+++ b/tests/Framework/Charset.php
@@ -71,6 +71,7 @@ class Framework_Charset extends PHPUnit_Framework_TestCase
             array('&BCAEMARBBEEESwQ7BDoEOA-', 'Рассылки', 'UTF7-IMAP', 'UTF-8'),
             array('Рассылки', '&BCAEMARBBEEESwQ7BDoEOA-', 'UTF-8', 'UTF7-IMAP'),
             array(base64_decode('GyRCLWo7M3l1OSk2SBsoQg=='), '㈱山﨑工業', 'ISO-2022-JP', 'UTF-8'),
+            array('㈱山﨑工業', base64_decode('GyRCLWo7M3l1OSk2SBsoQg=='), 'UTF-8', 'ISO-2022-JP'),
         );
     }