8老师：关于employment verification letter

HI,

I am now working as a postdoc, but REALLY truly tired of this bench work. I try to find another job in the same company, but the new job is not related with my NIW scope. If USCIS asks me for the employment verification letter, can I go back to do volunteer in a lab and ask HR to write such a EVL? Definitely it will not contain salary information. Will such EVL work for the ref?

Thanks a lot.