Android (Galaxy Tab 6) Will not reboot to bootloader
I resolved it. I discovered that its a problem that was quite common with the T580. I was mistaken about fastboot being on there. The issue is actually with the version of TWRP that was being used. It it for the T580, but does not work. This file must be used -- twrp_3.2.3-1_sm-t580_29918.tar . That version works flawlessly.