You put the wrong version of TWRP on your tablet probably? when you restart and it boots into TWRP, on the starting screen you should be able to use fastboot.
---------- Post added at 04:33 PM ---------- Previous post was at 04:31 PM ----------
When it happened to me, it was a bootloader and TWRP conflict: I flashed the jb version instead of the -42 Version. to fix it, I did fastboot reboot bootloader and then got back into android and flashed the correct one from Terminal Emulator. Or you could just flash it from there.
Google presented their brand new UI for tablets alongsidethe release of Android 3.0 Honeycomb back in early … more
01 Sep 2014
By Tomek Kondrat
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?