4.How to upgrade the JM21?
The JM21 supports online upgrade and local upgrade.
1.Online upgrade
If a new firmware is available and can be detected (with the JM21 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.
2.Local upgrade
Also, the JM21 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 JM21 or an SD card. Go to the "Technical Support->Firmware Upgrade->Local Upgrade" menu, and find the firmware package file to start the upgrade.
Notes:
1.Do not unzip the firmware package file.
2.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.
[The problem may occur in updating and the methods for solving]
The upgrade process takes about 5 to 20 minutes. After the upgrade, the system automatic rebooting will take 2 minutes, so please be patient.
1. If you encounter the problem that the system is stuck and cannot boot normally after the upgrade, please try a forced restart: press and hold the power button for about 10 seconds until the "FiiO" logo appears on the screen.
2. If you are using online update, the system prompts "invalid image", please go to "built-in storage-android-data-com.android.fiioupdate-files", delete this folder, and try online update again.
3. If you encounter system errors, please enter factory mode to restart/reset the machine:
In the off state, press and hold the JM21 volume down button, then plug in the USB charging cable, wait for the machine to turn on, that is, enter the factory (recovery) mode, select reboot system now to restart.
4.If the online upgrade fails, you can also try the local upgrade. If there is an error in the local upgrade, the copy or download of the installation package is generally damaged. Please download the installation package again.
