oppo R821 write flash failed..

here is log

Phone must be off with battery inside.
Please insert USB cable now…
Detected : MTK USB Port (COM11)
Phone detected…Please wait
Sending DA agent, please wait…
EMMC: (28Gb+4096Mb) HYNIX 0x2058494e5948
EMMC FW VERSION: 16:00:00:00:00:00:00:00
Detecting high speed port, wait……
If driver not installed, install high speed port driver.
Detected : DA USB VCOM Port (COM12)
Warning, flashing preloader disabled!
If you change android version, preloader must be flashed.
Starting flash.
Detected partitions count: 21
FORMAT EMMC FLASH : BEGIN:0x3bf40000 – LEN:0x7e00000
FORMAT EMMC FLASH : BEGIN:0x43d40000 – LEN:0x40000000
Download firmware to flash now…
After flash this firmware need to perform some aditional steps
1.Reinsert battery, keep VOL- and power on untill phone will come in factory mode
2.Select line EMMC, and after press home button.
3.Wait untill phone will restart and will stuck on logo(leave for 1 min in this stage).
4.If phone not power on, reinsert battery and perform direct unlock.
If repair fail, please contact us or report in forum to provide help.

device condition HANG ON OPPO logo
custamer say after download one app set be stuck on oppo logo.