Error updating ota. Anthalservice .

Hi guys, first of all m total stranger to androids. Recently bought htc desire 816 and updated it to 5.0.2. All was well
Until i got a new update notification with software number 2.34.75.2. I am currently on 2.34.75.1. Downloaded the update
But during installation i get error. My phone is not rooted or any mods applied to it.

E: missing bitmap oem_unlock_bg
(Code -1)
E:missing bitmap oem_unlock_bg_yes
(Code -1)
E:missing bitmap oem_unlock_bg_no
(Code -1)
E:find no match PARTITION: for package
ath @/cache/recover/block.map
Finding update package...
Opening update package...
Verifying update package...
Installing update...
L50QCT.01.401.016
Cleaning cache preload folder...
Verifying current system...
"/system/app/anthalservice/anthalservice.
apk" has unexpected contents.
E:error in @/cache/recovery/block.map
(Status 7)
Installation aborted.


Phone is working well after rebooting. Please help me solve this issue.note that my phone was brand new when i purchased
It and it hasnt been modded in any way.