Is the only way to interact with this device via their mobile app, and is the cable only for charging and firmware upgrades? There is no way to plug this in to a laptop, say, and interact with your wallets via Electrum or similar?
The proprietary connector is used only for charging the device. Firmware upgrades are transmitted via Bluetooth. There's no way to use it with any third-party app.
Note: I also got a test unit for a review.