All the credit goes to them for sharing this tool for free.If your phone shows the following error message you will have to enable the SIM access function in the Qualcomm baseband.

Credits : The QPST tool is created and distributed by Qualcomm Mobility Inc.

It is also officially provided by Qualcomm and comes with the QPST tool.

Alternative tool : The tool QFIL Flash is the best alternative to the QPST tool.

We therefore recommend that you make a backup of your data before using the QPST tool. Warning : Flashing any firmware using the QPST tool will erase your personal data from your Qualcomm device.You can download a bootloader only on a phone that uses NAND flash memory.

For a NAND Flash device, downloading a single image can send the NAND bootloader, phone image, or both to the phone. The tutorial only works on Qualcomm devices that use NOR and NAND Flash memory.Now disconnect your Qualcomm device from the computer and restart it.Once the flash is complete, you will see the green bar at the end of the flash.Now click on the Start button to begin the flashing process.Now under the boot image click on the browse button and locate the BOOT_LOADER.HEX file (included with the firmware).Now click on the Phone Image Browse button and locate on your computer the firmware (.hex) you want to install on your Qualcomm Device (assuming you have already downloaded the firmware to the computer).Now you will be able to see the QPST software download dialog box.Now click on the “Starts Clients” menu and select “Software Download”.Now connect your Qualcomm device to the computer using the USB cable.

Qualcomm qpst drivers