In this forum, there are too many wimps out of cowardice willing to sacrifice long-term self-welfare/sanity/dignity/self-esteem for short-term comfort and gain.
First of all, start yesterday to find a new job. This is the most important.
On top of that, you should do your best to win the HR case --- NO back-down! Let me explain why:
(1) You have nothing more to lose. Your boss already started the war since day one. He already took everything from you in the relationship. Since you have nothing more to lose, even the worst outcome from the HR's decision will be a win for you.
(2) People respect strength. Even evil person respects righteous people and treat them better. If there is chance for better (I am not saying "good") relationship with your boss (even if you will stay), it only *possibly* comes after you fight with all your strength. If you don't fight, there is no chance. 不打不相识 --- meaning people learn to live with each other; sometimes you have to go through loss-loss to reach win-win.
(3) Don't worry about the crap of "burning bridge". Your boss already burnt everything between you, leaving nothing for you to burn. And for that matter, since the HR process already started, you might still have some bridges left with your colleages if you do not give in.
(4) For your own long-term welfare in both mentality and career.
In sum, fight with the altitude of taking no prisoner, although your win odds admittedly are very low. What I said is only applicable to your today's specific situaion.
Let's me give a recent case: In Washington state, a *black* public employee was fired by the fire district because he slept during duty -- apparently his fault. He won the case with evidence that other white workers were never punished after faulting exactly the same. We can look at this case from tens of angles --- wimp's; racial; self-centered; Saint; Animals; etc.
Wish you the best luck.
