More BTLE-compliant firmware and operation
The fix for this issue would require both work here and work in the actual MetaWear firmware.
The current firmware for the device is not what one familiar with Bluetooth 4.0 Low Energy would classify as "compliant" with the standard.
The reason is that the current interface does not utilize a characteristic for each unique type of input or output, as required (or at least suggested) by the Bluetooth SIG's LE standard. Instead, the interface uses a single Command characteristic and a single Notify characteristic and codes the buffers in each to access different buffers within the device.
In a future update, making this more standards-compliant will allow a more streamlined interface, and a more modular code pattern, as well as remove a lot of the complexity of the interface code. As well, since the different mobile platforms are optimized for battery life around the use of unique characteristics, the mobile platforms will be able to be more battery-efficient.
If one is familiar with how the TI SensorTAG firmware is written, that is a much better example of how a more conventional BTLE interface should operate.