Set fuses so BOOTRST=1 on ATmega2560

This disables the Boot Reset vector which allows USBASP to be used for
Upload Using Programmer. Boot Reset vector is still enabled on all other
MCUs because it seems to work fine that way.  See
https://github.com/arduino/Arduino/issues/388 and
http://forum.arduino.cc/index.php?topic=126160.15

Author: per1234

avr/boards.txt

@@ -126,7 +126,7 @@ ariadne2560.upload.speed=115200
 
 ariadne2560.bootloader.tool=arduino:avrdude
 ariadne2560.bootloader.low_fuses=0xFF
-ariadne2560.bootloader.high_fuses=0xDA
+ariadne2560.bootloader.high_fuses=0xDB
 ariadne2560.bootloader.extended_fuses=0xFD
 ariadne2560.bootloader.unlock_bits=0x3F
 ariadne2560.bootloader.lock_bits=0x0F

avr/more-boards.txt

@@ -32,7 +32,7 @@ ariadne_debug.menu.model.atmega2560=ATmega2560 16MHz avr-developers.com, Blink,
 ariadne_debug.menu.model.atmega2560.upload.maximum_data_size=8192
 ariadne_debug.menu.model.atmega2560.upload.maximum_size=253952
 ariadne_debug.menu.model.atmega2560.bootloader.low_fuses=0xFF
-ariadne_debug.menu.model.atmega2560.bootloader.high_fuses=0xD0
+ariadne_debug.menu.model.atmega2560.bootloader.high_fuses=0xD1
 ariadne_debug.menu.model.atmega2560.bootloader.extended_fuses=0xFD
 ariadne_debug.menu.model.atmega2560.bootloader.unlock_bits=0x3F
 ariadne_debug.menu.model.atmega2560.bootloader.lock_bits=0x0F

boards.txt

@@ -73,7 +73,7 @@ ariadne2560_blink_shield.upload.maximum_size=258048
 ariadne2560_blink_shield.upload.speed=115200
 
 ariadne2560_blink_shield.bootloader.low_fuses=0xFF
-ariadne2560_blink_shield.bootloader.high_fuses=0xDA
+ariadne2560_blink_shield.bootloader.high_fuses=0xDB
 ariadne2560_blink_shield.bootloader.extended_fuses=0xFD
 ariadne2560_blink_shield.bootloader.path=ariadne
 ariadne2560_blink_shield.bootloader.file=ariadne_atmega2560_16mhz_blink_shield.hex

more-boards.txt

@@ -77,7 +77,7 @@ ariadne2560_debug.upload.maximum_size=253952
 ariadne2560_debug.upload.speed=115200
 
 ariadne2560_debug.bootloader.low_fuses=0xFF
-ariadne2560_debug.bootloader.high_fuses=0xD0
+ariadne2560_debug.bootloader.high_fuses=0xD1
 ariadne2560_debug.bootloader.extended_fuses=0xFD
 ariadne2560_debug.bootloader.path=ariadne
 ariadne2560_debug.bootloader.file=ariadne_atmega2560_debug_16mhz_blink_shield.hex