The process of using a Qualcomm Flash Loader typically involves:
edl /w boot boot.img
Contrary to popular belief, Qualcomm Flash Loader v10 isn't an app you "install" on your PC. Instead, it is a low-level protocol driver and a set of DLL files that allow high-level flashing tools (like QFIL, QPST, or MiFlash) to communicate with a Qualcomm chipset when the device is in Emergency Download (EDL) mode.