M8_ul OTA

I am tring to get ota to work on this phone but with no succes

Reading information...
Using Fastboot mode...
Reading common information
(bootloader) version: 0.5
(bootloader) version-bootloader:
(bootloader) version-baseband: 1.24.21331147A1.09G
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 4.16.1540.8
(bootloader) version-misc: PVT SHIP S-ON
(bootloader) serialno: HT4BJWM01188
(bootloader) imei: 3587160549xxxxx
(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: 3aa067db
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0
Execution time is 15(ms)

If I try to flash a rom with coresponding original cid I get "large image update fail" I managed to write a Brightstar rom but when I try OTA it doesn’t work.
How can I get ota to work on this device?