Because Firehose gives raw hardware access, it has also been used by security researchers to find vulnerabilities in the boot chain:
Would you like help identifying which Firehose file matches your specific Qualcomm device?
Without this precise loader, a deeply bricked Qualcomm phone cannot process flashing commands, effectively leaving it as a permanent paperweight. 1. How the Qualcomm Boot Chain and EDL Mode Work
To understand why a Firehose file is necessary, it helps to understand how a Qualcomm chip boots. The startup process moves through strict hierarchical stages:
The process of loading a Firehose programmer relies on a two-stage protocol sequence: