If the recorder firmware upgrade fails in the SleepImage App, your recorder may display a download icon (see below) on the screen and be unresponsive. Please follow the instructions below to resolve the problem using the nRF Toolbox app available on the Apple App Store and Google Play Store. Before you start, please email support@sleepimage.com to get a copy of the latest recorder firmware.
After you receive the firmware file (ZIP), save it under Files (iOS)/My Files (Android) on your mobile device.