SEPO

The SEPO (Security EPOch) tag specifies the device that the firmware is supposed to be ran on. It allows Apple to make sure you are not running another device's firmware files on an incompatible device, probably to prevent using old exploits.

Devices

 * Apple TV
 * 2G:
 * 3G:
 * 3G Rev A:
 * iPad
 * 1G:
 * iPad 2
 * Wi-Fi:
 * GSM:
 * CDMA:
 * Wi-Fi Rev A:
 * iPad 3
 * Wi-Fi:
 * GSM:
 * Global:
 * iPad 4
 * Wi-Fi:
 * GSM:
 * Global:
 * iPad mini
 * iPad mini 1G
 * Wi-Fi:
 * GSM:
 * Global:
 * iPhone
 * 2G: 0x04
 * 3G: 0x04
 * 3GS:
 * iPhone 4
 * GSM:
 * GSM Rev A:
 * CDMA:
 * 4S:
 * iPhone 5
 * GSM:
 * Global:
 * iPhone 5c
 * GSM:
 * Global:
 * iPhone 5s
 * GSM:
 * Global:
 * iPod touch
 * 1G: 0x04
 * 2G: 0x01 (later 0x02, then 0x04)
 * 3G:
 * 4G:
 * 5G: