Decreased stability
Devices often crash, native applications or third-party applications of iOS devices will flash back, and data contained in the applications will be lost.
security vulnerability
After jailbreaking, the device is easy to be used by criminals, the user's personal information is threatened by theft at any time, and the device will be more vulnerable to viruses.
Battery life is shortened
Once fully charged, the jailbreak device can no longer maintain its original battery life.
Audio/data loss
Audio will be lost during the call, data connection will be slow or unstable, and positioning data will be delayed or wrong.
cut off power
Applications such as voice mail, weather and stocks will be interrupted with the jailbreak of the device.
Affect software upgrade
Arranging plug-ins on iOS devices after jailbreaking is likely to cause irreparable losses and affect future system updates.
There is no warranty.
Apple has always opposed jailbreak, so after the recent successful jailbreak of iOS 8, Apple couldn't sit still. Recently, the company added a provision in the shopping policy of retail stores that jailbreak devices do not enjoy warranty to warn users not to try to jailbreak their iPhone and iPad.