If you have confirmed you have the correct file (e.g., preloader_k62v1_64_bsp.bin ), here is the standard procedure using SP Flash Tool:

The file is a critical binary component used in the boot sequence of devices powered by MediaTek (MTK) System-on-Chips (SoCs), most notably seen in budget-friendly smartphones like the Redmi 9A . This file functions as a "preloader," which is the first piece of code the processor executes to initialize hardware—such as the DRAM (system memory)—before handing off control to the main operating system bootloader. Understanding the Filename Components