First, download the latest official firmware.
I was flashing version A422_012_024_140507_WW_CALL_FUSE
it is only for Lenovo A3000-H (it can be viewed under the back cover).
You can also find the firmware on the forum for example
The necessary driver and program Flash_tool must be in the archive, if not, then download them separately.
Run “Flash_tool” as Administrator.
Click on “Scatter-loading” and in the folder “target_bin” choose a file “MT6589_Android_scatter_emmc“.
Put a tick on “DA DL All With Check Sum“, as well as on “FAC” and clicking on the name “FAC” choose a file “fac.img“, then click “Firmware – Upgrade“.
Now remove the cover from the tablet by pressing and holding the RESET button, which is under the cover, connect the tablet to the computer and release the button. The first time the driver should be installed and the firmware process will start, waiting for the green circle to appear. The process lasts about 5-10 minutes. If the process started and stopped after a minute (a battery emblem appeared on the tablet), press the power button (do not hold) and the process will continue further.
When a green circle appears in the program, then the firmware process is complete, you can disconnect the cable from the tablet and turn it on.