USB-to-WiFi adapter not working with Linux 6.15 (driver issue?) (no replies)

Dear All,

I've installed a USB-to-WiFi adapter in a Neatgear ReadyNAS RN102. The box is now able to scan for WiFi networks, but is unable to connect. The error message is "No DHCPOFFERS received". Connecting fails the same way on a second network.

The adaper is a TP-Link AC600 Archer T600U Nano. It's the kind of adapter that barely extends out of the USB connector on the box. Some details after a fresh reboot:

root@rn102:~# uname -a
Linux rn102 6.15.2-mvebu-370xp-tld-1 #1 PREEMPT Sun Jun 22 21:40:09 PDT 2025 armv7l GNU/Linux

root@rn102:~# cat /etc/debian_version 
12.11

root@rn102:~# lsusb
Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 002 Device 002: ID 2357:011e TP-Link AC600 wireless Realtek RTL8811AU [Archer T2U Nano]
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub


root@rn102:~# lsmod
Module                  Size  Used by
rtw88_8821au           12288  0
rtw88_8821a            32768  1 rtw88_8821au
rtw88_88xxa            20480  1 rtw88_8821a
rtw88_usb              20480  1 rtw88_8821au
rtw88_core            139264  3 rtw88_88xxa,rtw88_usb,rtw88_8821a
mac80211              569344  2 rtw88_core,rtw88_usb
cfg80211              339968  2 rtw88_core,mac80211
snd_soc_spdif_tx       12288  0
snd_soc_kirkwood       20480  0
snd_soc_simple_card    20480  0
snd_soc_simple_card_utils    20480  1 snd_soc_simple_card
snd_soc_core          163840  4 snd_soc_spdif_tx,snd_soc_kirkwood,snd_soc_simple_card_utils,snd_soc_simple_card
rfkill                 24576  1 cfg80211
libarc4                12288  1 mac80211
snd_compress           20480  1 snd_soc_core
ac97_bus               12288  1 snd_soc_core
snd_pcm_dmaengine      12288  1 snd_soc_core
snd_pcm                90112  5 snd_soc_kirkwood,snd_compress,snd_pcm_dmaengine,snd_soc_simple_card_utils,snd_soc_core
snd_timer              32768  1 snd_pcm
sg                     36864  0
snd                    73728  4 snd_compress,snd_timer,snd_soc_core,snd_pcm
soundcore              12288  1 snd
g762                   16384  0
uio_pdrv_genirq        16384  0
uio                    16384  1 uio_pdrv_genirq
mvneta                 49152  0
mvneta_bm              12288  1 mvneta
phylink                40960  1 mvneta


root@rn102:~# dmesg | grep -A 1 rtw
[   27.777522] rtw_8821au 2-1:1.0: Firmware version 42.4.0, H2C version 0
[   28.157401] random: crng init done
[   29.525924] usbcore: registered new interface driver rtw_8821au
[   29.886528] rtw_8821au 2-1:1.0 wlx0123456789ab: renamed from wlan0
[   30.014116] rtw_8821au 2-1:1.0 wlan1: renamed from wlx0123456789ab
[   30.105256] warning: `iwconfig' uses wireless extensions which will stop working for Wi-Fi 7 hardware; use nl80211

root@rn102:~# head /etc/network/interfaces
auto lo eth0
iface lo inet loopback

# Wireless network
rename /wlx*=wlan1
allow-hotplug wlan1
iface wlan1 inet dhcp
    wpa-ssid essid
    wpa-psk password

root@rn102:~# ip a | tail -2
5: wlan1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 01:23:45:67:89:ab brd ff:ff:ff:ff:ff:ff

root@rn102:~# ip link set wlan1 up

root@rn102:~# ip a | tail -2
5: wlan1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 01:23:45:67:89:ab brd ff:ff:ff:ff:ff:ff

root@rn102:~# iwlist wlan1 scan | head -13
wlan1     Scan completed :
          Cell 01 - Address: AA:BB:CC:DD:EE:FF
                    Channel:1
                    Frequency:2.412 GHz (Channel 1)
                    Quality=62/70  Signal level=-48 dBm  
                    Encryption key:on
                    ESSID:"essid"
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s
                              9 Mb/s; 12 Mb/s; 18 Mb/s
                    Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s
                    Mode:Master
                    Extra:tsf=00000001ecb6177e
                    Extra: Last beacon: 80ms ago

root@rn102:~# ifup wlan1
Internet Systems Consortium DHCP Client 4.4.3-P1
Copyright 2004-2022 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/wlan1/01:23:45:67:89:ab
Sending on   LPF/wlan1/01:23:45:67:89:ab
Sending on   Socket/fallback
DHCPDISCOVER on wlan1 to 255.255.255.255 port 67 interval 7
DHCPDISCOVER on wlan1 to 255.255.255.255 port 67 interval 13
DHCPDISCOVER on wlan1 to 255.255.255.255 port 67 interval 10
DHCPDISCOVER on wlan1 to 255.255.255.255 port 67 interval 11
DHCPDISCOVER on wlan1 to 255.255.255.255 port 67 interval 7
DHCPDISCOVER on wlan1 to 255.255.255.255 port 67 interval 8
No DHCPOFFERS received.
No working leases in persistent database - sleeping.

root@rn102:~# iwconfig wlan1
wlan1     IEEE 802.11  ESSID:off/any  
          Mode:Managed  Access Point: Not-Associated   Tx-Power=20 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:on

The firmware (not the driver) for the adapter is missing in Debian 12 (bookworm), so I just copied it from my laptop running Debian 13 (trixie):

root@rn102:~# md5sum /usr/lib/firmware/rtw88/rtw8821a_fw.bin
b5fdc50011a441dba8fc140fbbedc342  /usr/lib/firmware/rtw88/rtw8821a_fw.bin

This post says that the driver '8821au' was replaced by 'mac80211' in kernel version 6.13. Both are installed (see 'lsmod' output above). I tried blacklisting the 'rtw88_*' modules, but then the fimware is not loaded and no 'wlx*' device is registered. Is this the issue and, if so, what's the fix?

Regards,
Trond Melen