EDL mode or Emergency Download Mode is a special boot mode in Qualcomm Android devices that allows OEMs to force-flash firmware files. This mode is also commonly used by power users to unbrick their devices if the bootloader or the system is corrupted12.
When in EDL mode, the device identifies itself as “Qualcomm HS-USB QDLoader 9008” over a USB connection and implements the Firehose or Sahara protocol to accept commands for flashing1. You can use tools like QPST, QFIL, MSMDownload, etc. to flash the firmware on your device in EDL mode12.
There are different ways to enter EDL mode on Qualcomm devices, such as using ADB command, Fastboot command, test points, or EDL deep flash cable34. The method may vary depending on your device model and software version.
I hope this explains what EDL mode is and how it works. Let me know if you have any other questions!