[Q] Want to go back on stock!pls Help htc one m8x taiwan 3.28.709.6 topic

C:\adb>fastboot getvar all
(bootloader) version: 0.5
(bootloader) version-bootloader: 3.19.0.0000
(bootloader) version-baseband: 1.22.21331147A1.29G
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 3.28.709.6
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) serialno: HT43SWM05796
(bootloader) imei: ******************
(bootloader) imei2: Not Support
(bootloader) meid: 00000000000000
(bootloader) product: m8_ul
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B11000
(bootloader) cidnum: HTC__621
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: on
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) commitno-bootloader: df77f8b7
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0

htc one m8x Taiwan
1st I relock my bootloader then enter in RUU mode and flash the firmware,which I downloaded from htc website( http://www.htcdev.com/devcenter/downloads) of my veriate and getting error 12 signature verification failed.

using latest venom rom with twrp recovery. PLS HELP I WANT TO GO BACK TO STOCK.