Multiple devices with the same serial are not supported

[christxph]

If you have connected multiple devices with the same serial (which, unfortunately, frequently happens with cheap Chinese devices), then you can only access one of them in adb idea.

This can be fixed by accessing devices using the -t instead of the -s flag:

-t ID      use device with given transport id
-s SERIAL  use device with given serial (overrides $ANDROID_SERIAL)

The transport id is assigned by the host system and unique per USB port, whereas the device serial is set by the manufacturer and quite a few manufacturers seem to not care about making the serial uniqiue.

The transport ids can be found out using:

> adb devices -l
List of devices attached
0123456789ABCDEF       device usb:338886656X product:xyz model:xyz device:xyz transport_id:56
0123456789ABCDEF       device usb:338886656X product:xyz model:xyz device:xyz transport_id:57

As you see, the serial is the same, but the transport_id differs between those devices.

Check this Stackoverflow answer for more information: https://stackoverflow.com/a/29966699

[pbreault]

That's an interesting bug. Thanks for the root cause analysis. Out of curiosity, does Studio see them as separate devices?

[christxph]

Android Studio doesn't detect them, instead it shows either just one of the devices or just Unknown:

while adb devices returns all connected devices.