Purpose
Modifying system-level partitions carries a risk of permanent hardware damage. While prog_emmc_firehose_8953_ddr_mbN is a robust tool, incorrect usage (such as interrupting the process) can leave the device unrecoverable without expensive JTAG/ISP equipment.
Only download these files from reputable GSM forums or developer hosting sites. Malicious programmer files can contain scripts that damage your bootloader.