Unable to upgrade my HTC 826 to Android M via OTA updates

[prateek23]

Hi All,

I have recently received OTA Marshmellow update for my HTC Desire 826 Dual SIM. I have not rooted my phone. But while installing the update, recovery screen appears with below error msgs. I tried after factory reset but didn't work. Can anyone help me to understand what this means ? and how it can be solved ?

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 path @/cache/recover/block.map
Finding update package...
Opening update package...
Verifying update package...
Installing update...
L50QCT. 01 . 103 . 015
Verifying current system...
system partition has unexpected contents
E:Error in @/cache/recovery/block.map
(Status 7)

Installation aborted.

 

[anon(632115)]

Check this out How to Fix Status 7 Error While Installing OTA Update or Custom ROMs

 

[prateek23]

That topic relates to sideloading update, I'm not sideloading them (manually installing them), and the solution stated there is to flash stock rom which I'm unable to find. Is there any other way of fixing this?