yes you need unlock the tablet and then boot per fastboot after you can flash twrp in twrpD*mn... Tried my forgotten thor, rooted on 13.3.1. 0, but unused for 6years now. Failed to boot to twrp (stuck on grey logo). Tried with twrp 3.5.0_9-0 and -1 by using flashify. Is there any other way to boot Into twrp?