The provisions of this article, exclusive of the provisions of Sections 10240, 10240.3, 10242.5, and 10242.6, do not apply to any bona fide loan secured directly or collaterally by a first trust deed, the principal of which is thirty thousand dollars ($30,000) or more, or to any bona fide loan secured directly or collaterally by any lien junior thereto, the principal of which is twenty thousand dollars ($20,000) or more.