Redwood City, California
There are downsides to hiring graduates of any school, not just HBCUs. The challenge in the hiring process is identifying people with the skills you need to help grow your business. The school the applicant attended is just one factor. Employers will look at all factors (including experience, certifications, volunteer work, etc.) on a resume when making a hiring decision. Some companies may have stricter qualifications than others (only hiring from certain schools). However, that is not typical.
Make yourself attractive to a company by becoming a well rounded candidate in addition to your educational background.