The high-granularity calorimeter (HGCAL) will replace the current endcap calorimeters of the CMS experiment in the high-luminosity era. The first part of the talk will summarize our R&D activities on the silicon-based HGCAL modules. Our efforts toward standardizing module assembly procedures will be discussed. We will then review the development of quality control and assurance studies for various module components. Lastly, we will go through the latest measurements of ultra-legacy electron trigger scale factors for full Run-2 data using the ‘Tag and Probe’ method; these will be useful for our ongoing and planned physics studies.