This paper investigates the influence of different epoxy molding compound (EMC) materials on the reliability of mirrored NOT-AND gate (NAND) component placement (Mirrored NAND) in Flash Ball Grid Array (BGA) packages, addressing a critical issue in electronic packaging. The project aims to close the knowledge gap regarding how variations in EMC materials impact the reliability of lead-free solder joints under thermal cycling conditions. By isolating the effects of EMC material, we aim to provide precise insights into its impact on crack severity within the solder joint array. Our methodology involves subjecting the Mirrored NAND Flash BGA packages to thermal cycling tests (TCT) ranging from 500 to 800 cycles, followed by dye and pull (DnP) testing which refer to observe and analyze crack severity. Despite the occurrence of cracks, both types of EMC materials used in this study enabled the packages to meet the stringent reliability criterion of less than 50% solder joint cracking on functional solder balls. The key findings from this study reveal differences in crack severity behavior based on the EMC material used under thermal stress. These insights not only advance knowledge in the field but also contribute to the development of more sustainable and reliable electronic devices.