Can not connect to Wi-Fi with N-Only

[bxwllzz]

USB Wi-Fi device: COMFAST CF-WU725B (RTL8723BU). Wi-Fi router: ASUS RT-AC1200G+ and ASUS RT-AC54U. Platform: Windows, Ubuntu 16.04 and Raspberry Pi 3B (Debian 9.0 Stretch).

Windows

Everything is fine on Windows.

Both on Ubuntu 16.04 and Raspberry Pi 3B:

• It works fine when connect to the hotspot Wi-Fi from iPhone or Windows 10.
• When connect to my Wi-Fi router (distance: about 20cm), if I set Wi-Fi mode to Auto, it connects successfully. But if set to N-Only, it can not connect with association timeout error.

wpa_supplicant -dd:

...
wlan1: Cancelling scan request
wlan1: WPA: clearing own WPA/RSN IE
wlan1: Automatic auth_alg selection: 0x1
RSN: PMKSA cache search - network_ctx=0x195dbf8 try_opportunistic=0
RSN: Search for BSSID c8:3a:35:22:ad:91
RSN: No PMKSA cache entry found
wlan1: RSN: using IEEE 802.11i/D9.0
wlan1: WPA: Selected cipher suites: group 16 pairwise 16 key_mgmt 2 proto 2
wlan1: WPA: Selected mgmt group cipher 32
wlan1: WPA: clearing AP WPA IE
WPA: set AP RSN IE - hexdump(len=22): 30 14 01 00 00 0f ac 04 01 00 00 0f ac 04 01 00 00 0f ac 02 0c 00
wlan1: WPA: using GTK CCMP
wlan1: WPA: using PTK CCMP
wlan1: WPA: using KEY_MGMT WPA-PSK
wlan1: WPA: not using MGMT group cipher
WPA: Set own WPA IE default - hexdump(len=22): 30 14 01 00 00 0f ac 04 01 00 00 0f ac 04 01 00 00 0f ac 02 00 00
wlan1: State: SCANNING -> ASSOCIATING
nl80211: Set wlan1 operstate 0->0 (DORMANT)
netlink: Operstate: ifindex=7 linkmode=-1 (no change), operstate=5 (IF_OPER_DORMANT)
Limit connection to BSSID c8:3a:35:22:ad:91 freq=2462 MHz based on scan results (bssid_set=0)
wlan1: set_disable_max_amsdu: -1
wlan1: set_ampdu_factor: -1
wlan1: set_ampdu_density: -1
wlan1: set_disable_ht40: 0
wlan1: set_disable_sgi: 0
wlan1: set_disable_ldpc: 0
wlan1: Determining shared radio frequencies (max len 1)
wlan1: Shared frequencies (len=0): completed iteration
nl80211: Set mode ifindex 7 iftype 2 (STATION)
nl80211: Unsubscribe mgmt frames handle 0x891d4029 (mode change)
nl80211: Subscribe to mgmt frames with non-AP handle 0x195c8a0
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=040a
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=040b
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=040c
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=040d
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=090a
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=090b
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=090c
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=090d
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=0409506f9a09
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=7f506f9a09
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=0801
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=06
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=0a07
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=0a11
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=1101
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=1102
nl80211: Register frame type=0xd0 (WLAN_FC_STYPE_ACTION) nl_handle=0x195c8a0 match=0505
nl80211: Key management set PSK
nl80211: Connect (ifindex=7)
  * bssid=c8:3a:35:22:ad:91
  * bssid_hint=c8:3a:35:22:ad:91
  * freq=2462
  * freq_hint=2462
  * SSID - hexdump_ascii(len=6):
     48 43 35 37 36 31                                 HC5761          
  * IEs - hexdump(len=28): 30 14 01 00 00 0f ac 04 01 00 00 0f ac 04 01 00 00 0f ac 02 00 00 7f 04 00 00 0a 02
  * WPA Versions 0x2
  * pairwise=0xfac04
  * group=0xfac04
  * akm=0xfac02
  * htcaps - hexdump(len=26): 63 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  * htcaps_mask - hexdump(len=26): 63 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  * vhtcaps - hexdump(len=12): 00 00 00 00 00 00 00 00 00 00 00 00
  * vhtcaps_mask - hexdump(len=12): 00 00 00 00 00 00 00 00 00 00 00 00
  * Auth Type 0
nl80211: Connect request send successfully
wlan1: Setting authentication timeout: 10 sec 0 usec
EAPOL: External notification - EAP success=0
EAPOL: External notification - EAP fail=0
EAPOL: External notification - portControl=Auto
wlan1: Authentication with c8:3a:35:22:ad:91 timed out.
Added BSSID c8:3a:35:22:ad:91 into blacklist
TDLS: Remove peers on disassociation
wlan1: WPA: Clear old PMK and PTK
wlan1: Request to deauthenticate - bssid=00:00:00:00:00:00 pending_bssid=c8:3a:35:22:ad:91 reason=3 state=ASSOCIATING
TDLS: Tear down peers
wpa_driver_nl80211_disconnect(reason_code=3)
wlan1: Event DEAUTH (12) received
wlan1: Deauthentication notification
wlan1:  * reason 3 (locally generated)
Deauthentication frame IE(s) - hexdump(len=0): [NULL]
wlan1: CTRL-EVENT-DISCONNECTED bssid=c8:3a:35:22:ad:91 reason=3 locally_generated=1
wlan1: Auto connect enabled: try to reconnect (wps=0/0 wpa_state=5)
wlan1: Setting scan request: 0.100000 sec
wlan1: Radio work 'connect'@0x195d258 done in 10.008565 seconds
BSSID c8:3a:35:22:ad:91 blacklist count incremented to 2
wlan1: Blacklist count 2 --> request scan in 500 ms
wlan1: Ignore new scan request for 0.500000 sec since an earlier request is scheduled to trigger sooner
TDLS: Remove peers on disassociation
wlan1: WPA: Clear old PMK and PTK
wlan1: Disconnect event - remove keys
wlan1: State: ASSOCIATING -> DISCONNECTED
...

[lwfinger]

What make/model of access point are you using? Does it have the latest firmware?

Please post the output of 'sudo iw phy'.

[bxwllzz]

sudo iw phy on Ubuntu 16.04.

Wiphy phy2
    max # scan SSIDs: 9
    max scan IEs length: 2304 bytes
    Retry short limit: 7
    Retry long limit: 4
    Coverage class: 0 (up to 0m)
    Supported Ciphers:
        * WEP40 (00-0f-ac:1)
        * WEP104 (00-0f-ac:5)
        * TKIP (00-0f-ac:2)
        * CCMP (00-0f-ac:4)
    Available Antennas: TX 0 RX 0
    Supported interface modes:
         * IBSS
         * managed
         * AP
         * monitor
         * P2P-client
         * P2P-GO
    Band 1:
        Capabilities: 0x1862
            HT20/HT40
            Static SM Power Save
            RX HT20 SGI
            RX HT40 SGI
            No RX STBC
            Max AMSDU length: 7935 bytes
            DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: 16 usec (0x07)
        HT TX/RX MCS rate indexes supported: 0-7, 32
        Bitrates (non-HT):
            * 1.0 Mbps
            * 2.0 Mbps
            * 5.5 Mbps
            * 11.0 Mbps
            * 6.0 Mbps
            * 9.0 Mbps
            * 12.0 Mbps
            * 18.0 Mbps
            * 24.0 Mbps
            * 36.0 Mbps
            * 48.0 Mbps
            * 54.0 Mbps
        Frequencies:
            * 2412 MHz [1] (20.0 dBm)
            * 2417 MHz [2] (20.0 dBm)
            * 2422 MHz [3] (20.0 dBm)
            * 2427 MHz [4] (20.0 dBm)
            * 2432 MHz [5] (20.0 dBm)
            * 2437 MHz [6] (20.0 dBm)
            * 2442 MHz [7] (20.0 dBm)
            * 2447 MHz [8] (20.0 dBm)
            * 2452 MHz [9] (20.0 dBm)
            * 2457 MHz [10] (20.0 dBm)
            * 2462 MHz [11] (20.0 dBm)
            * 2467 MHz [12] (20.0 dBm)
            * 2472 MHz [13] (20.0 dBm) (no IR)
            * 2484 MHz [14] (disabled)
    Band 2:
        Capabilities: 0x1862
            HT20/HT40
            Static SM Power Save
            RX HT20 SGI
            RX HT40 SGI
            No RX STBC
            Max AMSDU length: 7935 bytes
            DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: 16 usec (0x07)
        HT TX/RX MCS rate indexes supported: 0-7, 32
        Bitrates (non-HT):
            * 6.0 Mbps
            * 9.0 Mbps
            * 12.0 Mbps
            * 18.0 Mbps
            * 24.0 Mbps
            * 36.0 Mbps
            * 48.0 Mbps
            * 54.0 Mbps
        Frequencies:
            * 5170 MHz [34] (disabled)
            * 5180 MHz [36] (disabled)
            * 5190 MHz [38] (disabled)
            * 5200 MHz [40] (disabled)
            * 5210 MHz [42] (disabled)
            * 5220 MHz [44] (disabled)
            * 5230 MHz [46] (disabled)
            * 5240 MHz [48] (disabled)
            * 5260 MHz [52] (disabled)
            * 5280 MHz [56] (disabled)
            * 5300 MHz [60] (disabled)
            * 5320 MHz [64] (disabled)
            * 5500 MHz [100] (disabled)
            * 5520 MHz [104] (disabled)
            * 5540 MHz [108] (disabled)
            * 5560 MHz [112] (disabled)
            * 5580 MHz [116] (disabled)
            * 5600 MHz [120] (disabled)
            * 5620 MHz [124] (disabled)
            * 5640 MHz [128] (disabled)
            * 5660 MHz [132] (disabled)
            * 5680 MHz [136] (disabled)
            * 5700 MHz [140] (disabled)
            * 5745 MHz [149] (disabled)
            * 5765 MHz [153] (disabled)
            * 5785 MHz [157] (disabled)
            * 5805 MHz [161] (disabled)
            * 5825 MHz [165] (disabled)
            * 5920 MHz [184] (disabled)
            * 5940 MHz [188] (disabled)
            * 5960 MHz [192] (disabled)
            * 5980 MHz [196] (disabled)
            * 6000 MHz [200] (disabled)
            * 6020 MHz [204] (disabled)
            * 6040 MHz [208] (disabled)
            * 6060 MHz [212] (disabled)
            * 6080 MHz [216] (disabled)
    Supported commands:
         * new_interface
         * set_interface
         * new_key
         * start_ap
         * new_station
         * set_bss
         * join_ibss
         * set_pmksa
         * del_pmksa
         * flush_pmksa
         * remain_on_channel
         * frame
         * set_channel
         * connect
         * disconnect
    Supported TX frame types:
         * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
    Supported RX frame types:
         * IBSS: 0xd0
         * managed: 0x40 0xd0
         * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
         * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
         * P2P-client: 0x40 0xd0
         * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
    WoWLAN support:
         * wake up on anything (device continues operating normally)
    software interface modes (can always be added):
         * monitor
    interface combinations are not supported
    Device supports scan flush.
Wiphy phy1
    max # scan SSIDs: 9
    max scan IEs length: 2304 bytes
    Retry short limit: 7
    Retry long limit: 4
    Coverage class: 0 (up to 0m)
    Supported Ciphers:
        * WEP40 (00-0f-ac:1)
        * WEP104 (00-0f-ac:5)
        * TKIP (00-0f-ac:2)
        * CCMP (00-0f-ac:4)
    Available Antennas: TX 0 RX 0
    Supported interface modes:
         * IBSS
         * managed
         * AP
         * monitor
         * P2P-client
         * P2P-GO
    Band 1:
        Capabilities: 0x1862
            HT20/HT40
            Static SM Power Save
            RX HT20 SGI
            RX HT40 SGI
            No RX STBC
            Max AMSDU length: 7935 bytes
            DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: 16 usec (0x07)
        HT TX/RX MCS rate indexes supported: 0-7, 32
        Bitrates (non-HT):
            * 1.0 Mbps
            * 2.0 Mbps
            * 5.5 Mbps
            * 11.0 Mbps
            * 6.0 Mbps
            * 9.0 Mbps
            * 12.0 Mbps
            * 18.0 Mbps
            * 24.0 Mbps
            * 36.0 Mbps
            * 48.0 Mbps
            * 54.0 Mbps
        Frequencies:
            * 2412 MHz [1] (20.0 dBm)
            * 2417 MHz [2] (20.0 dBm)
            * 2422 MHz [3] (20.0 dBm)
            * 2427 MHz [4] (20.0 dBm)
            * 2432 MHz [5] (20.0 dBm)
            * 2437 MHz [6] (20.0 dBm)
            * 2442 MHz [7] (20.0 dBm)
            * 2447 MHz [8] (20.0 dBm)
            * 2452 MHz [9] (20.0 dBm)
            * 2457 MHz [10] (20.0 dBm)
            * 2462 MHz [11] (20.0 dBm)
            * 2467 MHz [12] (20.0 dBm)
            * 2472 MHz [13] (20.0 dBm) (no IR)
            * 2484 MHz [14] (disabled)
    Band 2:
        Capabilities: 0x1862
            HT20/HT40
            Static SM Power Save
            RX HT20 SGI
            RX HT40 SGI
            No RX STBC
            Max AMSDU length: 7935 bytes
            DSSS/CCK HT40
        Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
        Minimum RX AMPDU time spacing: 16 usec (0x07)
        HT TX/RX MCS rate indexes supported: 0-7, 32
        Bitrates (non-HT):
            * 6.0 Mbps
            * 9.0 Mbps
            * 12.0 Mbps
            * 18.0 Mbps
            * 24.0 Mbps
            * 36.0 Mbps
            * 48.0 Mbps
            * 54.0 Mbps
        Frequencies:
            * 5170 MHz [34] (disabled)
            * 5180 MHz [36] (disabled)
            * 5190 MHz [38] (disabled)
            * 5200 MHz [40] (disabled)
            * 5210 MHz [42] (disabled)
            * 5220 MHz [44] (disabled)
            * 5230 MHz [46] (disabled)
            * 5240 MHz [48] (disabled)
            * 5260 MHz [52] (disabled)
            * 5280 MHz [56] (disabled)
            * 5300 MHz [60] (disabled)
            * 5320 MHz [64] (disabled)
            * 5500 MHz [100] (disabled)
            * 5520 MHz [104] (disabled)
            * 5540 MHz [108] (disabled)
            * 5560 MHz [112] (disabled)
            * 5580 MHz [116] (disabled)
            * 5600 MHz [120] (disabled)
            * 5620 MHz [124] (disabled)
            * 5640 MHz [128] (disabled)
            * 5660 MHz [132] (disabled)
            * 5680 MHz [136] (disabled)
            * 5700 MHz [140] (disabled)
            * 5745 MHz [149] (disabled)
            * 5765 MHz [153] (disabled)
            * 5785 MHz [157] (disabled)
            * 5805 MHz [161] (disabled)
            * 5825 MHz [165] (disabled)
            * 5920 MHz [184] (disabled)
            * 5940 MHz [188] (disabled)
            * 5960 MHz [192] (disabled)
            * 5980 MHz [196] (disabled)
            * 6000 MHz [200] (disabled)
            * 6020 MHz [204] (disabled)
            * 6040 MHz [208] (disabled)
            * 6060 MHz [212] (disabled)
            * 6080 MHz [216] (disabled)
    Supported commands:
         * new_interface
         * set_interface
         * new_key
         * start_ap
         * new_station
         * set_bss
         * join_ibss
         * set_pmksa
         * del_pmksa
         * flush_pmksa
         * remain_on_channel
         * frame
         * set_channel
         * connect
         * disconnect
    Supported TX frame types:
         * IBSS: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * managed: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * AP: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * AP/VLAN: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * P2P-client: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
         * P2P-GO: 0x00 0x10 0x20 0x30 0x40 0x50 0x60 0x70 0x80 0x90 0xa0 0xb0 0xc0 0xd0 0xe0 0xf0
    Supported RX frame types:
         * IBSS: 0xd0
         * managed: 0x40 0xd0
         * AP: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
         * AP/VLAN: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
         * P2P-client: 0x40 0xd0
         * P2P-GO: 0x00 0x20 0x40 0xa0 0xb0 0xc0 0xd0
    WoWLAN support:
         * wake up on anything (device continues operating normally)
    software interface modes (can always be added):
         * monitor
    interface combinations are not supported
    Device supports scan flush.

[bxwllzz]

On the PCB of the COMFAST CF-WU725B, only one antenna is connected.

More Test

• B Only is OK. 11 Mb/s
• G Only is OK. 54 Mb/s
• N Only fails. dmesg:

  ...
  [ 2257.911267] RTL871X: start auth
  [ 2257.913165] RTL871X: auth success, start assoc
  [ 2261.614071] RTL871X: nolinked power save enter
  [ 2264.697080] RTL871X: RTW_ADAPTIVITY_EN_AUTO, chplan:0x20, Regulation:3,3
  [ 2264.697082] RTL871X: RTW_ADAPTIVITY_MODE_NORMAL
  [ 2265.219571] RTL871X: nolinked power save leave
  [ 2269.428722] RTL871X: rtw_set_802_11_connect(wlx40a5ef430adc)  fw_state=0x00000008
  [ 2269.685924] RTL871X: start auth
  ...

• B/G mixed is OK. 54 Mb/s
• G/N mixed is OK. 72.2 Mb/s
• B/G/N mixed + 20 MHz is OK. 72.2 Mb/s
• B/G/N mixed + 20/40 MHz is OK. 150 Mb/s

  AP Settings

  

[maurerr]

the same issue in my case - tp-link mr200 4g router with padavan-ng firmware (ralink/mediatek wisoc) . switched from N-only to NG-mixed fixed the issue