Can I hold the equity of 1% in my friends start up while on H1-B?

I am on H1-B working for MNC in bay area. I have a question like, Can I hold the equity of 1% in my friends start up(C-Corp)? My friend is GC holder. I invested some money, so in return he would like to give some equity. I am not going to hold any position in my friends company. Can you please clarify. Thanks!