[Q] Hardbricked black screen topic

If I power on the phone without a USB connected I see a black screen for 1 second and then it shuts off. When I power it on through USB the black screen stays on. No download mode. Windows detects it as Unknown device. I have the drivers downloaded and LG Flash tool started but it won't recognize it as a serial device.

History:
Phone came with 12B. Flashed original stock firmware with LG Flash tool. Rooted and flashed twrp. Installed SkyDragon rom and running that for a few days without issue. Look at phone today and it's off and won't turn on. Maybe the OTA update came and bricked it?

[Q] nexus 7 hardbricked??? please help!!!!! topic

i recently rooted my nexus 7 2013 FLO as part of a car install.
after installing it into the car i realized kitkat and lollipop no longer allow tethering so i read up on some forums and found threads saying i could modify system files in order to make it work. Here is the link i was following "m.pocketnow.com/2015/01/01/nexus-6-tethering" (sorry could not add complete link as i am a new member)
I did both the settings.db and build.prop mod and now my nexus will not respond. initially after restarting, i would receive the google logo and then go to a blank backlit screen, and then i tried getting it into recovery mode by pressing all 3 buttons when it was on and now it will not do anything.
i have tried N7 root toolkit and it does not even see it.
i hope i have not killed my N7.

any help would be great
thanks