A hydrocracking system is upgraded by modifying an existing ebullated bed initially utilizing a supported ebullated bed catalyst to thereafter utilize a dual catalyst system that includes metal sulfide catalyst particles and supported ebullated bed catalyst. The upgraded hydrocracking system achieves at least one of: (1) hydroprocess lower quality heavy oil; (2) increase conversion of higher boiling hydrocarbons that boil at 524° C. (975° F.) or higher; (3) reduce the concentration of supported ebullated bed catalyst required to operate an ebullated bed reactor at a given conversion level; and/or (4) proportionally convert the asphaltene fraction in heavy oil at the same conversion level as the heavy oil as a whole. The metal sulfide catalyst may include colloidal or molecular catalyst particles less than 1 micron in size and formed in situ within the heavy oil using a catalyst precursor well-mixed within the heavy oil and decomposed to form catalyst particles.