F620K FRP Error

Hello!
I have LG F620K with FRP lock. i try to reset FRP but dont't work.

Phone mode is DOWNLOAD
Start reset FRP...
Laf Protocol: 01000002
Model name: LG-F620K
Software verion: F620K10l
Android verion: 5.1.1
Target operator: KT
Target country: KR
Chipset: msm8916
IMEI: 352896071372838
Init EXT4 ...
Laf cmd info: send LAF_CMD_COPY, retry #1
Laf cmd info: send LAF_CMD_COPY, retry #2
Laf cmd info: send LAF_CMD_COPY, retry #3
Laf cmd error: LAF_CMD_COPY could not write.
Error reset locks
Elapsed: 53 secs. --> (v9.48)

Now phone restart on logo. i flash firmware from suport but now pone its hang on lock. what i can do?
BR!