Alright I tried as you said setting everything manually at boot time.
auto wlan0
iface wlan0 inet dhcp
up iwconfig wlan0 mode Auto
up iwconfig wlan0 essid ElmPie
This really doesn't do anything except trying to get an IP address at boot time which doesn't work.
I also tried giving it an IP and essid at boot time
auto wlan0
iface wlan0 inet static
address 192.168.254.20
netmask 255.255.255.0
network 192.168.254.0
broadcast 192.168.254.255
up iwconfig wlan0 mode Auto
up iwconfig wlan0 essid ElmPie
When I do this iwconfig gives me this :
wlan0 IEEE 802.11g ESSID:"ElmPie"
Mode:Auto Frequency:2.462GHz Access Point: 66:F1:74:30:2D:17
Bit Rate:54Mb/s Tx-Power:16 dBm
RTS thr:2347 B Fragment thr:2346 B
Encryption key

ff
Power Management

ff
Link Quality:100/100 Signal level:-57 dBm Noise level:-256 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
I wonder where he gets that Access Point MAC address because its not correct either.
and
ifconfig this :
wlan0 Link encap:Ethernet HWaddr 00:0C:41:64:AD:7F
inet addr:192.168.254.20 Bcast:192.168.254.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 KiB)
Interrupt:17 Memory:da000000-da001fff
but all of this doesn't make it work
I'm almost out of ideas ;(