I have an nvidia shield tablet (shieldtablet), and I was running BlissPop. It was slow, and kept giving me an error when it was trying to update, so I decided to try a different ROM. So I downloaded the lineageOS ROM and tried to flash it.

However, TWRP kept giving me an error when I tried to flash the ROM. I don't remember exactly what the error was.

So, I thought that I needed to update TWRP. I tried through the "Official TWRP" app, but after doing so I was unable to boot into recovery mode at all. I could still get to the bootloader, but when I tried to select recovery mode it would give me an error and dump me back out to the bootloader menu.

I tried installing TWP through the "TWRP Manager" app, but it simply says that it was unsuccessful, without any other information.

I tried doing this using ADB. I connected the tablet, enabled USB debugging. If i do the ">adb devices" command, I can see the tablet. Then I did >adb reboot bootloader - which works, it reboots the device into the bootloader. But then I try and flash recovery and nothing happens, it just says <waiting for device>. And if I do > fastboot devices it doesn't list any devices.

I don't know what else to try at this point