ls980 device model is different

LG ls980
i modified build.prop for unlock purpose but now the phone is showing LG logo then blank display. I tried to flash via LG FLASH TOOLS but it shows "device model is different" but in download mode the model is correct ie ls980

I modified the following things in build.prop
FROM
ro.carrier=unknown
ro.build.target_operator=SPR
persist.service.crash.enable=0
ro.telephony.default_network=10
telephony.lteOnCdmaDevice=1

TO
ro.carrier=spr
ro.build.target_operator=spr
persist.service.crash.enable=1
ro.telephony.default_network=0
telephony.lteOnCdmaDevice=0

please help me to unbrick
I read on the internet to modify file model number via hex editor, but to which model do i modify, actual model is ls980 and it also shows ls980 in download mode too