Documentation

Make sure Bluetooth is enabled on your phone and the device is powered on. BLE advertising stops during Wi-Fi mode - if the device's web UI is open, close it. Scan range is roughly 10 metres.

Stay close to the device during transfer (within 1–2 m). The AMOLED firmware has smaller BLE buffers than ST7789 - if you're on AMOLED and seeing frequent failures, try reducing the transfer window in settings. This will be fixed in a future firmware update.

Some EPUB files use non-standard chapter structures. Try opening the file in Calibre and re-exporting as EPUB 3 with a proper table of contents.

The Android app draws its screens with Android System WebView and needs version 111 or newer; the notice shows the version this device has. Update "Android System WebView" in the Play Store and reopen the app. Many e-readers without the Play Store get WebView updates only with the device maker's system updates. If yours has none, use lesefluss.app in an up-to-date browser on another device.

Make sure the device is in dev mode (You can set it in the Android app). Try disconnecting and reconnecting USB, then re-running the upload script.