Overmax Basecore 10 ii (reset/firmware reset/recover)
I found this topic while I was trying to factory reset a basecore 9, with no luck. But I just performed a factory reset on a basecore 10 so I'm sharing the experience with you. 

Due to its "missing" volume buttons its not that simple. You have to  connect a USB keyboard to it. ( I hope your device has USB hub also)


You have to shut down your device, and wait for 20 seconds. 
Hold down Power button and the other (house like) button until the Recovery menu appears. 
In the menu, you can navigate with your keyboard's Up and Down buttons, but the "Enter" button will be the Power button.


I hope it helps. Good luck, have a nice day :)