Firehose files are critical in the process of flashing or modifying firmware on Qualcomm-based smartphones, like the Poco X3 Pro. Essentially, a firehose file is used by Qualcomm's flashing tool, known as Qualcomm Flash Image Loader (QFIL) or part of the QPST (Qualcomm Product Support Tools) package, to communicate with the device and flash images to it.