mkc

I am having problem unzipping the four files inside "update_MYGICA_S812_S802_Device_5.1_20170612" for my Mygica 1800E for the Android 5.1 upgrade. They zip files are boot, bootloader, logo and recovery. Since WinRar will not unzip these files, I use 7-zip but still getting errors saying there are some data after payload data. How does everyone else unzip these files? Appreciate if someone can let me know how to unzip these files.