[X3non]

Often atimes, one might find his / her device stuck in fastboot mode. Whether you purposefully booted into this mode or not, you should be able to exit using any of the methods below

How to Exit Fastboot Mode

Reboot using Fastboot

1. Setup adb and fastboot on your PC using the guide @ https://forum.hovatek.com/thread-588.html 
   
2. Connect the phone to the PC
   
3. Type in the command into adb CMD prompt window and hit Enter after each line
   • fastboot devices 
     
   • fastboot reboot
     
4. The device should reboot
   
5. If fastboot is unable to recognize your device, then it's likely due to old adb and fastboot. refer to https://forum.hovatek.com/thread-17105.html
   

Reboot using Power Button

• Simply Press and hold the power button on your device till the device restarts
  

Reboot using Hardware Buttons on Nokia Phones

• Simply Press and hold Vol up + Vol down + power button on your device till the device restarts. Once the Nokia logo shows up, first release the power button then subsequently both vol buttons
  

Power Off by Removing Battery

• Simply take out / reinsert the battery of the device, then power it back on
  

Power Off by Battery Draining

• Simply leave the phone in that state till it runs out of battery, then charge the device and power it back on.
  

Hardware buttons / Firmware

• If your device has a specific hardware key combo for booting into fastboot, you might want to check these buttons and ensure they're not stuck
  
• If all else fails, then search for, download and flash firmware for your device model