Step 1

$ rkunpack ~/Desktop/update.img
rkunpack: info: RKFW signature detected
rkunpack: info: version: 5.0.2
rkunpack: info: date: 2015-11-20 17:04:51
rkunpack: info: family: rk3368
rkunpack: info: 00000066-0001c9b3 BOOT                       (size: 117070)
rkunpack: info: 0001c9b4-121ba1b7 embedded-update.img        (size: 303683588)

Step 2

$ rkunpack ~/Desktop/embedded-update.img
rkunpack: info: RKAF signature detected
rkunpack: info: file size matches (303683588 bytes)
rkunpack: info: manufacturer: RK30SDK
rkunpack: info: model: rk312x
rkunpack: info: number of files: 13
rkunpack: info: 00000800-00000800 package-file               (size: 661)
rkunpack: info: 00001000-00001037 rk3126MiniLoaderAll(L)_V2.20.bin (size: 112974)
rkunpack: info: 0001d000-0001d000 rk312x.parameter.txt       (size: 831)
rkunpack: info: 0001d800-0001e000 Image/uboot.img            (size: 4194304)
rkunpack: info: 0041e000-0041e018 Image/misc.img             (size: 49152)
rkunpack: info: 0042a800-0042a924 Image/resource.img         (size: 598016)
rkunpack: info: 004bd000-004bd987 Image/kernel.img           (size: 4995108)
rkunpack: info: 00981000-00981d70 Image/boot.img             (size: 7045120)
rkunpack: info: 01039800-0103a808 Image/recovery.img         (size: 8404992)
rkunpack: info: 0183e000-0185f27e Image/system.img           (size: 278130688)
rkunpack: info: 1217d800-1217d83d backupimage/backup.img     (size: 124928)
rkunpack: info: 1219c800-1219c800 update-script              (size: 933)
rkunpack: info: 1219d000-1219d000 recover-script             (size: 266)
unpacked