The simple “quick fix” to the so-called “hard reset” of the C3 device.
Just use a metallic paper clip or wire to short circuit two points on the circuit board. Be careful to only touch the specified two points. This will reset the device. No data will be lost.
Please see the image, explaining how to do the hard reset. The hard reset can be performed multiple times without any risk of damaging the device.
Hard reset is needed when e.g. the C3 device stops broadcasting the Bluetooth ID, which is resulting in a failure to establish a connection to the Cortrium app.
We have not yet found the reason why the C3 device stops occasionally to broadcasting the Bluetooth ID. Naturally, we will investigate further and let you know when we have a firmware update solving the issue.