Similar issue... no LG logo at all
I was successful in rooting then attempted to install TWRP. The phone turned off then turned on with the "android open stomach and !" icon... it shut off a few mins later.
Now, all I get is the buzz when you power it on and a black screen. Im not able to enter the recovery mode using any combination of buttons. I cant even see the LG logo!
LG Mobile Support Tool nor my computer will even recognize the device. Am I truly bricked beyond repair?