Seems I found a way to semi brick my SM-T500. I was attempting to install the LOS 18.1 ROM just posted in the guide section. Some how I got the "can only install official" error message on my download screen after flashing TWRP. Made the mistake of flashing only the stock AP without BL or CSC and now I can't get into either recovery or download modes. Holding vol up and down and plugging in USB cable does nothing. Same with holding power button and either vol up or down. Blank screen. Can only power on and boot to system.