Update failed stock rom

[Guest barnir]

Heya guys im using stock rom from MEO in portugal on my Y300, im trying to update using OTA (i dont know where to get the oficial update from MEO without OTA) and when it restart on recovery i get something like this:

 

Checking patch files... assert failed: apply_patch_check("/fat/image/amshd.mbn", "hash code", "hash code")

 

and it reboots without update, i have the update.zip that OTA downloaded on my internal memory, can you guys give me any help about this?