Apple 5s itunes recovery failed? Solution for itunes recovery failure

IOS firmware version is not correct

1. Using itunes to upgrade the system we should be aware that we want to upgrade the IOS firmware system to be consistent with our phone, otherwise it may cause the phone to fail to restore Oh, here we download the system firmware we need to look at the firmware is not compatible with our version oh.

2. Alternatively, we can choose to have itunes download the firmware automatically in the itunes recovery interface. This does not occur because the firmware version is not correct.

IOS Firmware not compatible

1. We download good firmware is likely to be compatible oh, if not compatible with this problem will occur.

2. If there is a problem with the firmware, we can download a firmware again to upgrade on it.

Computer system problems

1. If we see an ITunes quote code 21 error. This time we may be a DNS problem, we just have WiFi or computer for DNS repair OH.