Press and hold both the and Volume Down buttons simultaneously for about 5 seconds.
Think of it as the official "factory service tool." Unlike the standard OxygenOS OTA updates or the fastboot commands that enthusiasts typically use, MSMDownloadTool operates at a much lower level. It communicates directly with the Qualcomm chipset during a specific mode known as .
MSMDownloadTool is a proprietary, Windows-based software utility used by OnePlus (and originally developed by Qualcomm) to flash firmware onto devices with Qualcomm Snapdragon processors.