Android - fastboot doesn't see device

Linux/OSX

Run fastboot as root or with sudo.

Other OS: credits

Are you rebooting the device into the bootloader and entering fastboot USB on the bootloader menu?

Try:

adb reboot bootloader

Then, look for on-screen instructions to enter fastboot mode.

Problem solved. At the end I saw that drivers for android were not installed. I installed drivers from this site http://forum.xda-developers.com/showthread.php?t=2126036 and device is visible by fastboot. One thing I don't understand is why adb saw device and fastboot not.