1) Download the full system image from Google. Untar and unzip.
2) Fastboot flash the bootloader (4.18). Fastboot reboot bootloader. Verify that the version is correct and updated.
3) Fastboot flash the STOCK 4.2.2 RECOVERY. Do not attempt to use CWM or TWRP, otherwise you will have issues.
4) Fastboot flash the 1231_0.17... radio.
5) Reboot into (stock) recovery mode.
6) At this point, the stock recovery should begin to process the radio update and do the actual installation of it. You will see the progress bar moving. When it's done, the tab will automatically reboot into normal mode.
7) Verify that your radio (in system settings) is updated to the latest version.
8) Reflash custom recovery if you want.