Android 6 Master Control Panel Bonded DFU + Android 6 gets stuck in a loop

[Clem Taylor]

I'm not sure why I didn't notice this sooner.

When trying to do a bonded DFU with a Nexus 6P and Master Control Panel it seems to get stuck in a loop reconnecting.

I connect, bond and trigger a DFU and then MCP disconnects, reconnects, disconnects in a loop. It never attempts to trigger the switch to the bootloader.

However if I manually write the start command to the DFU control point, everything works just fine.

Android 5.1.1 on a Nexus 4 works just fine.

master-control-panel-log.txt or: gist.github.com/.../a51e30a8a41d5f02bb3c

[Aleksander Nowakowski]

Hi, the reason thy it gets in a loop is that the DFU Version is always read as 0.1, which means that that's the application mode, not the bootloader mode. If it works when you manually write the start command, it means that the chip restarts after it disconnects, and does not start the DFU mode at all (or does, but immediately resets afterwards). The question is why..? I'm not quite sure. Nexus 4 sends just 1 packet each connection interval so it's very slow. Maybe it gives more time to the device to set itself up. We don't have the 6P yet, so it's hard to test, but it's a metter of time only.

Did you try the DFU with nRF Toolbox? It has a slightly newer version of the DFU library... There is a small chance it would work.

[Aleksander Nowakowski]

One more thing. Since some time the DFU lib waits 1 second before it start connecting to the target. Also it waits after switching from app to bootloader mode. Maybe that's why it does not end up in a loop, like MCP does (the current version of MCP was release some time ago and may not have this delay implemented, I don't remember).