spd sc6820/sc8810 stopped working

please help me about this
everytime i write my backup bin
on merapi tools after erase file
writing 0% merapi tools stopped working
11:40:36 Internal version: SPRD3
11:40:36 Boot downloading…
11:40:36 Start boot please wait a moment….
11:40:38 Spreadtrum Boot Block version 1.1
11:40:38 Boot downloading…
11:40:38 CPU TYPE:SC8810/6820 [88100040]
11:40:38 Boot downloading…
11:40:39 Flash ID: 00EC00BC006A
11:40:39 Flash Type:[SAMSUNG] K9F4G08/K9K4G08
11:40:39 FLASH LEN:0x20000000
11:40:39
11:40:39 Flash erasing,take a few minutes..
11:41:20 Writing…(0)