Lockbit configuration

Using Arduino Avrdude, stk500, Bootloader issues
1

Hi Guys!

I want to protect my Arduino from cloning.
The most i can do against it, that is set the correct Fuses/Lock bit trough AVRDUDE on SPI port.
I got USBASP, Extreme Burner AVR, so i can set the Fuses/Lock bit's.

I uses this calculator:

https://eleccelerator.com/fusecalc/fusecalc.php?chip=atmega2560&LOW=62&HIGH=D9&EXTENDED=FF&LOCKBIT=C0

But i am totally confused in settings.
What i need to set? I want to prevent code downloading into hex file. If i disable it, can i upload a new code trough bootloader? Or i need to disable Bootloader to for fully safety?

Névtelen

Do i need to uncheck the "Serial program downloading (SPI) enabled; [SPIEN=0] *" line?
What sould i chose from the buttom menu? Disable LPM, SPM?

What's the different from this menu? Wich one i need to configure?

Névtelen

If you can write me the correct fuses/lock bit values for my needs, then i will be pleased!

Thank you for yours answers

2

There is no way to protect your code without getting rid of the bootloader.

3

Thank you! What do you think, these settings are okey?:

So i disabled "Serial program downloading (SPI) enabled; [SPIEN=0] *" and set all Lock Bit settings to disabled

4

I have Read a lot. Now i understood some thing, but i have some question.

So the methode is: We write a program in Arduino IDE. Then compiled program saved in .hex file on the local PC. I load this hex file with Extreme Burner AVR program, and i set the lock bit to 0x00, then burn the program.

  • In this case after we upload the program, the lock bit are set, so i cannot read eeprom and flash memory with AVRDUDE-like program. It's true?

  • When i write with ISP programmer and "Boot Reset vector Enabled (default address=$0000); [BOOTRST=0]" unchecked, then the bootloader automaticly deleted?

  • In this case i am protected from beign cloned? :smiley:

5

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