DIY: Universal EDL cable

for Qualcomm-based KaiOS devices

by Luxferre

Since we have a lot of Qualcomm-based devices, some of them can be quirky to guess how to enter EDL mode, or how to do it correctly. For instance:

  • with Alcatel you have to first hold both volume keys, then only one of them;
  • for CAT B35 you have to hold * and #;
  • for 8110 you have to hold Up and Down, and during this you must insert the cable.

Sometimes you feel being out of spare hands.

So, a very simple cable mod comes in handy which requires no soldering at all.

1. Get a spare microUSB cable and strip the insulation somewhere in the middle;

2. Detect the D+ and GND wires (usually green and black) and strip the insulation on them.

This operation is necessary to allow the two cables to connect temporarily to send the signal to the PC that a device in EDL mode is connected (see the following diagram).

Done! You have just transformed a simple, common and inexpensive microUSB cable into a necessary tool to perform operations in EDL mode on Qualcomm-based devices. In fact an official cable with connector and which may require welding would require costs and not easy availability.

How to use it

1. Turn off the phone and connect the microUSB end of the cable to it;

2. Press the stripped wires against each other and connect USB plug to the PC;

3. Keep holding the wires for at least 5 seconds, then disconnect them from each other;

4. Disconnect the wires from each other. Now the PC should detect the phone in EDL mode (USB PID 9008.

See the video on Vimeo with the illustration and tests on 3 different phones

Have fun, Army of hardcore!