iOS 5 beta 7 redsn0w 0.9.8b7c越狱失败

提示错误AppleBCMWLAN::handleIOKitBusyWatchdogTimeout(): Error, no successful firmware download after 60000 ms|| Giving up...

换redsn0w 0.9.8 b7b也错误 

解决方法，重刷固件，直接越狱