Unhappy [SOLVED] Unable to install new HTC ONE update!

Hey guys! So, I got a pop up on my phone last week for the 4.4.2 update However, I seem to be unable to install it. I get booted into twrp, so I try to install it from there, but it says flash failed. I am completely hopeless with things like this (wasn't me who rooted my phone etc). Any help would be very appreciated and apologies for my stupid question.