Thank you @Gabriel-Ongpauco. Still no luck with that modification and i am writing blinker.ino test sketch which is only 2% of the max memory. Sketch uses 948 bytes (2%) of program storage space. Maximum is 32256 bytes. Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes. Writing | ################################################## | 100% 3.33s avrdude: 32768 bytes of flash written avrdude: verifying flash memory against /tmp/sketch.hex: avrdude: load data flash data from input file /tmp/sketch.hex: avrdude: input file /tmp/sketch.hex auto detected as Intel Hex avrdude: input file /tmp/sketch.hex contains 32768 bytes avrdude: reading on-chip flash data: Reading | #################################################> ERROR, flash NOT successful Flash complete! | 100% 3.27s avrdude: verifying ... avrdude: verification error, first mismatch at byte 0x0000 0xff != 0x0c avrdude: verification error; content mismatch avrdude done. Thank you.