If you want to install custom ROMs using a custom recovery such as CWM or TWRP on your Verizon Galaxy Note 2 SGH-i605, you will need to unlock the bootloader.
This is for older builds, for latest Unlock method, see here instead.
Do I need to unlock bootloader if I have another Galaxy Note 2?
NO!!! Only Verizon Galaxy Note 2 comes with its bootloader unlocked, thanks to Verizon. So, please do not try this UNLESS YOU HAVE A Verizon Galaxy Note 2 SCH-i605!!!
So, let’s go ahead and unlock our bootloader.
Step 1. Before we begin, go to Settings->About phone on your Verizon Note 2 and see that last couple letters under Build number, it should say VRALJB.
Step 2. Once you are on Build number VRALJB, you can proceed. Power off your Verizon Note 2 then boot into ODIN download mode by holding down Volume Down, Home Center, and Power buttons together for about 5 seconds.