Arduino as ISP: Invalid device signature

I had an issue with my 3d printer, its a tevo tarantula with a board of type mks base v1.4.
This means its based on arduino mega. The problem was with the arduino mega firmware itself - its gone.
So I am trying to use another Arduino Mega (a normal one) as a programmer to burn bootloader on the 3d printer as a target. Everything is connected good to the ICSP:

   Arduino MEGA 2560  |    Pin    |  Pin number on  
    as ISP programmer |    Name   |  target: ATMega 2560
 IC-Pin 19 (SS) 53 ....... Reset .... IC-Pin 1
 IC-Pin 20 (SCK) 52 ...... SCK ...... IC-Pin 20
 IC-Pin 21 (MOSI) 51 ..... MOSI ..... IC-Pin 21
 IC-Pin 22 (MISO) 50 ..... MISO ..... IC-Pin 22          
        GND .............. GND ...... IC-Pin 11/32/62/81
        5V ............... VCC ...... IC-Pin 10/31/61/80

I have the "Arduino as ISP" program uploaded on my programmer.
Now when I try to burn the bootloader it sais:

avrdude: Yikes!  Invalid device signature.
         Double check connections and try again, or use -F to override
         this check.

An error occurred while uploading the sketch

I read online that I need to change stuff in my boards.txt, but because of the intro (the part about me having a 3d printer), I don't really know what to edit. Other than that, it sais something about overriding this error by using -F. Easy enough, I can do that. But where exactly do I use this -F thing?

Thanks in advance for any help,
Arad ^-^

Try pin 10 instead of pin 53 on programmer board. Newer version of Arduino ISP sketch uses this configuration to be identical with UNO if the ISP connector is used for the rest 5 wires.