Thanks a lot! tim and mlafauci both of you guys,
There is a one more thing to make it work out though,
1. do not use/download wrong files wifiHD.elf(50KB) and wifiHD.hex(2,002KB) directly from (https://github.com/mlafauci/Arduino/tree/wifishield-bugfix/hardware/arduino/firmwares/wifishield/wifiHD/Release
2. Do download a whole Arduino-wifishield-bugfix.zip(230MB) file from (https://github.com/mlafauci/Arduino/tree/wifishield-bugfix
), then use those firmware binary files; wifiHD.elf (708KB) and wifiHD.hex(703KB)
Somehow those two files are different within .zip and the github raw code. This is the reason for the parsing error is occurred, every time when I parse the .hex to compile on the AT32UC3A1512 chip, because I used wrong files.
Cheers, Arduino! Cheers, developers!