6. How to upgrade the M15S?
The M15S supports online upgrade and local upgrade.
If a new firmware is available and can be detected (with the M15S connected to an available internet), an upgrade notification will show up in the notification center. Tap on it to enter the update menu for the online upgrade. If there's no upgrade notification showing up, you can go to the ""Technical Support->Firmware Upgrade"" menu, and tap the ""Check for updates"" icon to check manually.
Also, the M15S can be upgraded locally by a firmware package. Download the firmware package file from FiiO website, and copy it to the internal storage of the M15S or an SD card. Go to the ""Technical Support->Firmware Upgrade->Local Upgrade"" menu, and find the firmware package file to start the upgrade.
1.Do not unzip the firmware package file.
2.Before the upgrade, ensure the power of the device is adequate (>30%) so to avoid upgrade failure.
3.If the device goes to factory mode which cannot detect the firmware, the reason may be that the firmware file is damaged. At this time, press the power button to reboot the device. Re-download the firmware file and restart the upgrade.