I have some very strange problems with mine peon and wifi.

If I boot the pi with an ethernet cable, all fine. Both ethernet AND the wifi interface works without any problem.

BUT if I boot only with wifi, the machine does not answer to wifi at all, unless I try to scan it with fing (a network utility).

Something like this:

Last login: Sat Jan 11 15:13:46 on ttys003
Gansobook-Pro:~ surak$ ping 192.168.10.147
PING 192.168.10.147 (192.168.10.147): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
Request timeout for icmp_seq 2
64 bytes from 192.168.10.147: icmp_seq=2 ttl=64 time=1791.952 ms
64 bytes from 192.168.10.147: icmp_seq=3 ttl=64 time=791.725 ms
64 bytes from 192.168.10.147: icmp_seq=4 ttl=64 time=74.386 ms
64 bytes from 192.168.10.147: icmp_seq=5 ttl=64 time=10.937 ms
Request timeout for icmp_seq 7
Request timeout for icmp_seq 8
Request timeout for icmp_seq 9
Request timeout for icmp_seq 10

Do you see those moments when the machine actually answered? That's when I ran this command on another window:

sudo fing -s 192.168.10.147 -o text,console

It does that EVERY TIME. If I boot with ethernet, the wireless works perfectly (?). I don't know what else to do.