question about H1B transfer (My company doesn't let me go!)

[lawfulgm]

Hi all

Let's say my current company is A, and the new company is B.

I've been working with a company A and got my H1B through company A. A couple month after H1B receipt, I got a job offer from company B.
They processed H1B transfer and it just got approved as of today.
I sent notification of resignation to my boss asking I would like to quit in two weeks, but my boss didn't approve and told me to work til Feb. 3rd.

The problem is that company B wants me to start ASAP.

If I ignore whatever my boss told me to do and start working for company B from Jan 30th, would it cause any problem ?

Thanks,

[immihelp]

Employment is voluntary. Therefore, you can quit at any time.