Hello Everyone
I have a confusion about fuse settings.
I read from various sources, to edit fuse byte settings, there are two ways.
The easiest way to change values of Fuses from boards.txt from Arduino directory
hardware/arduino/avr/boards.txt
and the other method is using AVRDUDE with Command Prompt
The question is if I used the first method and change Fuse values from boards.txt it requires burn
bootloader after change fuse values and requires edit bootloader or using the default bootloader?
I ask this question because I found when to working with internal 8MHz Oscillator and follow the
instructions in this page https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard
when to downloaded Breadboard ZIP and extract it, found special bootloader with it.
Thanks in Advance
To set fuses via the IDE you indeed burn a bootloader. Which bootloader to use it up to you but the default bootloader is for 16Mhz. It is possible to use the default bootloader on a 8Mhz Arduino just by changing the upload speed as well. Just use halve the speed 
septillion:
To set fuses via the IDE you indeed burn a bootloader. Which bootloader to use it up to you but the default bootloader is for 16Mhz. It is possible to use the default bootloader on a 8Mhz Arduino just by changing the upload speed as well. Just use halve the speed
Thank you for your reply and very helpful.
I hope, in some other inquiries If you don't mind.
Are there any changes in a bootloader hex file if fuse bytes changes? Whether or not to interfere in a bootloader.
Best Regards
The bootloader isn't affected by the fuse settings but it does rely on the clock speed you use.
I ask this question because I found when to working with internal 8MHz Oscillator
For 99% of standard Arduino playing, the fuses should remain unchanged from the factory setting. That 1% however opens the doors to lots of amazing things ... like 8MHz without a crystal, no bootloader so your recover additional flash memory, etc.
More than one newbie (and likely far more experienced coders if the truth was known) have gone down the rabbit hole never to return. Changing fuses is simple ... it looks simple ... the procedure is simple ... but the results can have profound affects on the uC ... to the point of bricking it.
If you mess with the fuses, do so on a DIP package uC that is socketed ... like the Atmega328P-PU ... replacements are easy to obtain already with a bootloader installed.
Before changing anything ... read the value first! Is the value read what was set as the default for that board (example: UNO)? If you find something different than expected... stop! Figure out what is happening before proceeding ...
Just a friendly warning from someone that has fat-fingered a few setting in the past :o
Ray