[Samsung Galaxy Nexus] cap'nC:
Hi, I did some test. I'm on r251-384MHz, maguro, XXLF1, ParanoidAndroid 2.1.2

Added ap_scan=1, no success: Can't get IP address. I let the phone try to connect for about 2 minutes.

Logcat when I switched wifi on:

D/WifiService( 316): setWifiEnabled: true pid=1675, uid=1000
D/SoftapController( 121): Softap fwReload - Ok
D/CommandListener( 121): Setting iface cfg
D/CommandListener( 121): Trying to bring down wlan0
I/wpa_supplicant( 1694): rfkill: Cannot open RFKILL control device
D/Tethering( 316): sendTetherStateChangedBroadcast 1, 0, 0
I/wpa_supplicant( 1694): rfkill: Cannot open RFKILL control device
D/CommandListener( 121): Setting iface cfg
D/CommandListener( 121): Trying to bring up p2p0
W/wpa_supplicant( 1694): wlan0: Failed to initiate AP scan
I/wpa_supplicant( 1694): wlan0: Trying to associate with [I]<mac address of my router>[/I] (SSID='[I]<my network>[/I]' freq=2447 MHz)
I/wpa_supplicant( 1694): wlan0: Associated with [I]<mac address of my router>[/I]
I/wpa_supplicant( 1694): wlan0: CTRL-EVENT-CONNECTED - Connection to [I]<mac address of my router>[/I] completed (auth) [id=0 id_str=]
E/DhcpStateMachine( 316): DHCP failed on wlan0: Timed out waiting for DHCP to finish
E/WifiStateMachine( 316): IP configuration failed
I/wpa_supplicant( 1694): wlan0: CTRL-EVENT-DISCONNECTED bssid=00:00:00:00:00:00 reason=0
D/CommandListener( 121): Clearing all IP addresses on wlan0
D/ConnectivityService( 316): ConnectivityChange for WIFI: DISCONNECTED/DISCONNECTED
D/ConnectivityService( 316): Attempting to switch to mobile
D/ConnectivityService( 316): Attempting to switch to BLUETOOTH_TETHER
D/ConnectivityService( 316): Attempting to switch to ETHERNET
D/ConnectivityService( 316): ConnectivityChange for WIFI: DISCONNECTED/DISCONNECTED
D/ConnectivityService( 316): Attempting to switch to mobile
D/ConnectivityService( 316): Attempting to switch to BLUETOOTH_TETHER
D/ConnectivityService( 316): Attempting to switch to ETHERNET
I/wpa_supplicant( 1694): wlan0: Trying to associate with [I]<mac address of my router>[/I] (SSID='[I]<my network>[/I]' freq=2447 MHz)
I/wpa_supplicant( 1694): wlan0: Associated with [I]<mac address of my router>[/I]
I/wpa_supplicant( 1694): wlan0: CTRL-EVENT-CONNECTED - Connection to [I]<mac address of my router>[/I] completed (reauth) [id=0 id_str=]
D/Tethering( 316): MasterInitialState.processMessage what=3
D/Tethering( 316): MasterInitialState.processMessage what=3
D/Tethering( 316): MasterInitialState.processMessage what=3
D/Tethering( 316): MasterInitialState.processMessage what=3

Logcat when I switched wifi off:

D/ConnectivityService( 316): handleInetConditionHoldEnd: net=0, condition=100, published condition=100
E/DhcpStateMachine( 316): DHCP failed on wlan0: DHCP result was failed
E/NotificationService( 316): Ignoring notification with icon==0: Notification(pri=0 contentView=null vibrate=null sound=null defaults=0x0 flags=0x1 kind=[null])

NOTE: I don't know when it happened, but after switching wifi off I found wpa_supplicant.conf at its original state, without the ap_scan line.

ap_scan=0, no success, same behaviour and very similar switch on logcat.

switch off:

D/ConnectivityService( 315): handleInetConditionHoldEnd: net=0, condition=100, published condition=100
D/WifiService( 315): setWifiEnabled: false pid=1679, uid=1000
D/CommandListener( 121): Clearing all IP addresses on wlan0
I/wpa_supplicant( 1703): CTRL_IFACE monitor[0]: 2 - No such file or directory
D/ConnectivityService( 315): ConnectivityChange for WIFI: DISCONNECTED/DISCONNECTED
D/ConnectivityService( 315): Attempting to switch to mobile
D/ConnectivityService( 315): Attempting to switch to BLUETOOTH_TETHER
D/ConnectivityService( 315): Attempting to switch to ETHERNET
D/ConnectivityService( 315): ConnectivityChange for WIFI: DISCONNECTED/DISCONNECTED
D/ConnectivityService( 315): Attempting to switch to mobile
D/ConnectivityService( 315): Attempting to switch to BLUETOOTH_TETHER
D/ConnectivityService( 315): Attempting to switch to ETHERNET
I/wpa_supplicant( 1703): p2p0: CTRL-EVENT-TERMINATING
I/wpa_supplicant( 1703): wlan0: CTRL-EVENT-TERMINATING
D/Tethering( 315): InitialState.processMessage what=4
D/Tethering( 315): sendTetherStateChangedBroadcast 0, 0, 0
E/DhcpStateMachine( 315): DHCP failed on wlan0: DHCP result was failed
D/Tethering( 315): MasterInitialState.processMessage what=3
D/Tethering( 315): MasterInitialState.processMessage what=3
D/Tethering( 315): MasterInitialState.processMessage what=3
D/Tethering( 315): MasterInitialState.processMessage what=3

r254: No success, same logcats plus this line:

E/WifiHW ( 316): Unable to open connection to supplicant on "wlan0": No such file or directory

r259: No success, same logcats but:

I/wpa_supplicant( 3000): wlan0: Associated with 00:00:00:00:00:00
I/wpa_supplicant( 3000): wlan0: CTRL-EVENT-CONNECTED - Connection to 00:00:00:00:00:00 completed (auth) [id=0 id_str=]
E/DhcpStateMachine( 332): DHCP failed on wlan0: Timed out waiting for DHCP to finish
E/WifiStateMachine( 332): IP configuration failed

Mac address was all zeros instead of the correct one from my router.

EDIT: Looks like I was too slow. Thank you anyway for the effort Franco :D