The Qualcomm Emergency Download mode, commonly known as Qualcomm EDL mode and officially known as Qualcomm HS-USB QD-Loader 9008 is a feature implemented in the

boot ROM The boot ROM is a type of ROM that is used for booting a computer system. There are two types: a mask boot ROM that cannot be changed afterwards and a boot EEPROM, which can contain an UEFI implementation. Purpose Upon power up, hardware usuall ...

of a

system on a chip A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memor ...

by Qualcomm which can be used to recover

bricked A brick (or bricked device) is a mobile device, game console, router or other consumer electronic device that is no longer functional due to corrupted firmware, a hardware problem, or other damage. The term analogizes the device to a brick's ...

smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...

s. On Google's

Pixel 3 The Pixel 3 and Pixel 3 XL are a pair of Android smartphones designed, developed, and marketed by Google as part of the Google Pixel product line. They collectively serve as the successors to the Pixel 2 and Pixel 2 XL. They were officially an ...

, the feature was accidentally shown to users after the phone was bricked.

Device support

For a device to support EDL it must be using Qualcomm hardware. The most widespread SoC from Qualcomm is the

Snapdragon ''Antirrhinum'' is a genus of plants commonly known as dragon flowers, snapdragons and dog flower because of the flowers' fancied resemblance to the face of a dragon that opens and closes its mouth when laterally squeezed. They are native to ...

Access

ADB

The

Android Debug Bridge The Android Debug Bridge (commonly abbreviated as adb) is a programming tool used for the debugging of Android-based devices. The daemon on the Android device connects with the server on the host PC over USB or TCP, which connects to the cli ...

can be utilized to get access to EDL mode, with the command adb reboot edl.

Windows

The Qualcomm Product Support Tool (QPST) is normally used internally by service center executives for low-level firmware flashing to revive Android devices from a hard-brick or to fix persistent software issues. To flash the firmware, the tool communicates with supported devices via EDL. The QPST has not been officially released by Qualcomm.

Linux

Qualcomm Download (QDL) is a tool to communicate with Qualcomm System On a Chip bootroms to install or execute code. The source code is maintained by Bjorn Andersson aka andersson.

References

Qualcomm {{Firmware and booting