iOS系统的降级要看该版本的固件验证是否关闭，如果关闭，就无法刷这个版本的固件，那么如何看固件的验证是否关闭呢？现在就为大家简单介绍一下
IPSW Downloads
by Just a Penguin
Download current and previous versions of Apple's iOS Firmware and receive notifications when new firmwares are released.
Step 1: Choose a product
（选择设备 Continue reading "iOS系统降级版本验证支持查询 Choose an IPSW for the iPhone"