I think my nexus 7 2012 is totally bricked?

Hi folks,

I think my nexus 7 2012 is totally bricked.

It was playing up getting stuck at the flying colours at startup,(has OS 4.44 kitty kat didn't upgrade to 5.0)

So I went into recovery mode and tried reset but got all these messages.

E:failed to mount /cache (Invalid argument)
E:Can't mount /cache/recovery / log
E:Can't open /cache/recovery / log
E:failed to mount / cache (Invalid argument)
E:Can't mount /cache/recovery/last_log
E:Can't open /cache/recovery/last_log
E:failed to mount /cache (Invalid argument)
E:Can't mount /cache/recovery/last_install
E:Can't open /cache/recovery/last_install
E:failed to mount /cache (Invalid argument)

Just keep restarting after this as far as the flying colours icon.

I went to this site

wugfresh.com/nrt

and downloaded the Nexus Root Toolkit v2.1.6 ran it and installed drivers, PC could see android device ok, toolkit got as far as downloading my android OS 4.4 but seemed to get stuck at the flashing process writing the bootloader I think.

Anyway to cut a long story short my nexus won't even power on now at all, no way to get to the fastboot screen and its showing in windows as an apx device, from reading other threads seems a total brick.
No way back from this I take it, unless a hardware repairor something else major.

Appreciate any advice
Thanks a lot
Joe