Desire 820_A51_DTUL_L50 how to flash firmware.zip

Dear friends;
Below you can see phone info.I made super cid using xtc2 and downloaded following stock firmware.zip but can not succeed to flash into device.I tried these methids but not successful.Bootloader is relocked.

1.Using sd card phone refused installation coz of large file size.
2.Using flashers like flashman and xtc2 clip it stopped the process.
3.Using fastboot below you can see the result:

Code:

C:\And>fastboot flash zip rom.zip
sending 'zip' (1509635 KB)...
OKAY [ 72.574s]
writing 'zip'...
(bootloader) signature checking...
FAILED (remote: 12 signature verify fail)
finished. total time: 169.491s


Code:

0PFJIMG_A51_DTUL_L50_DESIRE_SENSE60_MR_hTC_Asia_India_2.10.720.1_R_Radio_01.01.010_U10305041_08.01.50512_release_453048_signed_2_4.zip


Code:

Reading information...
Using Fastboot mode...
Reading common information
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: 01.01.010_U1030481_08.01.41119
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 1.23.709.1
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) serialno: HC4B5YC05424
(bootloader) imei: 3553860616517..
(bootloader) imei2: 3553860616517..
(bootloader) meid: 00000000000000
(bootloader) product: a51_dtul
(bootloader) platform: hTCBmsm8939
(bootloader) modelid: 0PFJ11000
(bootloader) cidnum: 11111111
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: on
(bootloader) build-mode: SHIP
(bootloader) boot-mode: RUU
(bootloader) commitno-bootloader: c5431ba6
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
(bootloader) mfg-name:
Execution time is 8(ms)
all: Done!