Lenovo Tab3 7 Essential (lenovo-tb3710i)

Contributors

 * Projjal

How to enter flash mode
While turned off, hold down the power button until the device vibrates and then, hold the volume up button immediately. You'll enter a recovery (stock or custom such as TWRP), from where you have to choose "Reboot to bootloader" (different in case of TWRP or other recoveries) to reboot to fastboot mode.