verification error; content mismatch about megacore

[MCUdude]

are you using the latest version of MegaCore? Both codes uploads fine on my ATmega128 running at 16MHz using a USB to serial converter. Have you tried using another programmer like Arduino as ISP?

EDIT: I can reproduce the error when using an Arduino sketch. When using int main(void) it works just fine. I'll have a look at it

[MCUdude]

I found the Issue! The good news is that there's nothing wrong with my core. The bad new is that there's nothing I can do about it..

You see, there is some kind of bug in AVRdude 6.0.1 (which Arduino IDE ships with) that gives this error. Running this code:

void setup() {
  DDRA = 0xff;
  DDRB = 0xff;
  DDRC = 0xff;
  DDRD = 0xff;
  DDRE = 0xff;
  DDRF = 0xff;
}

void loop() {
  PORTA ^= 0xff;
  PORTB ^= 0xff;
  PORTC ^= 0xff;
  PORTD ^= 0xff;
  PORTE ^= 0xff;
  PORTF ^= 0xff;

  delay(1000);
}

and uploading with AVRdude 6.0.1 using this command (generated by Arduino IDE):

/Applications/Arduino.app/Contents/Java/hardware/tools/avr/bin/avrdude -C/Users/Hans/Documents/Arduino/hardware/MegaCore/avr/avrdude.conf -v -patmega128 -cusbasp -Pusb -Uflash:w:/var/folders/_p/s3kykxss20bbhfmqcg0ctrp80000gn/T/build6448819071412050804.tmp/sketch_jun18a.cpp.hex:i 

gives this error:

Reading | ################################################## | 100% 0.28s

avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0100
         0xff != 0x0f
avrdude: verification error; content mismatch

avrdude done.  Thank you.

If I open Terminal (I'm using a mac by the way) and use the latest version of AVRdud, but still sticks with the same hex file and parameters:

avrdude -C/Users/Hans/Documents/Arduino/hardware/MegaCore/avr/avrdude.conf -v -patmega128 -cusbasp -Pusb -Uflash:w:/var/folders/_p/s3kykxss20bbhfmqcg0ctrp80000gn/T/build6448819071412050804.tmp/sketch_jun18a.cpp.hex:i 

This is the output:

Reading | ################################################## | 100% 0.21s

avrdude: verifying ...
avrdude: 720 bytes of flash verified

avrdude: safemode: hfuse reads as CE
avrdude: safemode: efuse reads as FF
avrdude: safemode: Fuses OK (E:FF, H:CE, L:BF)

avrdude done.  Thank you.

If you won't use the bootloader I guess you'll have to use a newer version of AVRdude. You should probably create an issue over at the Arduino Github page where you suggest bumping up to AVRdude 6.3.

EDIT: It seems like someone already have thought about it!

okay, I see. thank you. Seems to me that this bug only happens when I use 0xff, the default value for all the memory.