Hello, If you reduce the bootloader size on a 328p from 2kb to 1.5kb, is the .5kb available to the application? Is this space automatically available or do I have to change something on the Arduino IDE before I upload my code? Or do I need to upload using avrdude? Thanks, -ren

You need to change the fuse bits with an AVR programmer, see http://frank.circleofcurrent.com/fusecalc/fusecalc.php?chip=atmega328p

Thanks for the replies. Yes, I know to change the fuses and start address when I upload the bootloader using avrdude, but do I need to make any changes when I am uploading the application using the Arduino IDE? Is it set for the max size by default?

I do believe the IDE throws an error if your sketch is too big, the limit is set in boards.txt

If you reduce the bootloader size on a 328p from 2kb to 1.5kb, is the .5kb available to the application? Is this space automatically available or do I have to change something on the Arduino IDE before I upload my code? Or do I need to upload using avrdude? First of all, optiboot is currently 512…

renasis: Thanks for the replies. Yes, I know to change the fuses and start address when I upload the bootloader using avrdude, but do I need to make any changes when I am uploading the application using the Arduino IDE? Is it set for the max size by default? The boards.txt file tells the IDE abo…

Bootloader size

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tim7 April 11, 2011, 1:13am 3

See here for allowable boot-sector sizes, and the corresponding fuse-settings. Beware: the units are 16-bit words, not bytes (caught me out )
http://www.engbedded.com/fusecalc/

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Bootloader size

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