Which port are you using to access the Galileo? The serial port used to access the internal Linux terminal is the following:
- Galileo Gen1: The serial port is the one that seems like an audio 3.5mm jack. It looks like an audio port but it is the serial port used to access the internal terminal.
- Galileo Gen2: The serial port is the 6pin header next to the Ethernet jack.
For both boards, Galileo Gen1 and Galileo Gen2, you will need the correct serial cable to access the serial port and the internal Linux terminal. Please check this site to know which port and which cable you should use: Intel® Galileo Boards and Kits — Console Serial Cables