iPod touch 3Gen 升级到 iOS 5 后，无法从备份恢复相关数据

[Hlbice]

提示“iTunes could not restore the iPod because the backup was corrupt or not compatible with the iPod that is being restored”
1、还有可能恢复吗？
2、有什么工具可以读取备份文件，我只是想知道失去了什么数据。