please help ..desire 500

set come with htc logo

model : htc desire 500 dual sim 5060


Model : Z4DUG
IMEI : 357654051826579
Build : 1.27.707.2
CID : HTC__038
HBoot : 1.03.0001
MID : 0P3Z10000
Security : ON

flash with this file

RUU_Z4_DUG_JB412_SENSE50_hTC_Asia_WWE_1.27.707.2_R adio_14.15.50QD.26_14.14.50.1NU_release_389156_sig ned.exe

start flashing then one time restart but then reconnect but not start flash and give me a error .. " usb error 171 "

i have 2 confusion about this topic

confusion no 1…

i will try to unlock boot loder so after fash unlock bin then show unlock menu and ask yes and no so i will press vol up and press pwr but not work pwr switch but switch is working normal and press down and select no so pwr switch working why ….

confusion no 2…

press vol down so get recovery all menu like fastboot etc …

1st line say bootloader is lock or not so my bootloader is locker but 2nd row say " security warning " so my qus. is why not show every time this " security warning " msg some time show and some time not show ….

please help

thanks advance