For those who are trying to update a dead ak 2025...maybe you can try to download the following firmwares...
QS Ak 2025 and MP3 tools that recognses the ak2025 and also read correctly firmwares...
http://bbs.mydigit.cn/read.php?tid=127829
http://bbs.mydigit.cn/read.php?tid=109790
Mass tool for ak2025..comes with and adfuupdate.inf driver requiered for these chipset version 5.5
http://bbs.mydigit.cn/read.php?tid=138066
Nerver upgrade a firmware....only if your player is dead...you can try...this a china site....only ressource that i found for AK2025