I tried different ISPs (Arduino as ISP, USBisp, USBprog, Buspirate) and each have had its problem:
not able to read the whole flash of a ATmega2506 (two byte/three byte problem), fixed voltage, etc...
Therefore I decided to buy an AVR-ISP500 by Olimex.
Does this programmer really need about 8 minutes to read the complete flash of an ATmega2560???
On Linux I did this:
avrdude -C/usr/local/arduino-1.8.3/hardware/tools/avr/etc/avrdude.conf -v -pm2560 -c stk500v2 -P /dev/ttyACM0 -Uflash:r:FlashContent.hex:i
I experimented with different -B/-b settings...no change.
By the way: The target was powered so the Olimex could probe the voltage...
The output of avrdude was quite normal...no errors...but it was THAT slow....
In this regard (and presumably I did nothing wrong) : Is the AVRISP-MKII more speedy?
Is it difficult to patch the firmware to be able to talk to avrdude?
Thanks a lot for any help in advance!