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ALFA Adapters on NetHunter (Android) — OTG Setup Guide

學習目標（Learning goal）: By the end of this guide you will have your ALFA adapter connected to an Android phone running Kali NetHunter, visible inside the NetHunter chroot, and ready for monitor-mode tools — all powered by a USB OTG cable. 適用對象: Intermediate (rooting knowledge required) ｜ 前置需求: Rooted Android phone, NetHunter installed, OTG cable, an ALFA adapter with an in-kernel chipset (see below).

Concept: why Android is the hardest environment​

NetHunter is Kali Linux running inside a chroot on your Android device. The phone's kernel still does the real work — and phone kernels are not the Ubuntu kernel:

  1. In-kernel drivers: a chipset supported by mainline Linux (MT7612U, MT7610U, MT7921AUN) usually works, because NetHunter's kernel images include the mainline mt76 driver family.
  2. DKMS drivers: compiling Realtek DKMS drivers inside an Android chroot is painful — phone kernels rarely ship the headers and toolchain the build needs. The RTL8812AU can work on some devices, but treat it as a project, not a setup step.

Rule of thumb: for NetHunter, prefer the AWUS036ACM (MT7612U). It is the community's default NetHunter adapter for a reason.

Prerequisites​

  • Rooted Android phone with Kali NetHunter installed (the official NetHunter image, or the NetHunter Store app on a rooted device)
  • OTG cable (USB-C or micro-USB depending on your phone) — ideally with external power for high-power adapters
  • ALFA adapter with an in-kernel chipset: AWUS036ACM / AWUS036ACHM / AWUS036AXM / AWUS036AXML
  • A phone with a kernel new enough for your chipset (kernel 5.18+ for the MT7921AUN models)

Step 1: Check your kernel​

Some chipsets need a recent kernel. Open a terminal in the NetHunter app (or adb shell) and run:

uname -r

Expected output: something like 4.19.157-perf+ (older phones) or 5.15.xx-gki (newer). For the MT7921AUN adapters you need 5.18 or newer; the MT7612U works fine on 4.19.

You might be wondering — "Do I need a specific NetHunter kernel?" Yes — the NetHunter team builds kernels for a specific list of supported devices. Check the official device list first: an unsupported phone means no monitor-mode-capable kernel, and the adapter will never leave managed mode no matter what you do.

Step 2: Connect via OTG​

Plug the OTG cable into the phone, then the adapter into the OTG cable. On most phones a notification appears ("USB device connected"). Then confirm the adapter is seen by the kernel:

lsusb

Expected output (MediaTek models):

Bus 001 Device 002: ID 0e8d:7612 MediaTek Inc. MT7612U 802.11a/b/g/n/ac 2T2R Wireless Adapter

If lsusb shows nothing, the OTG cable is not supplying power or the phone is not in USB host mode — try a powered OTG hub (important for the AWUS036AXM/AXML, which draw more power).

Step 3: Verify the interface inside NetHunter​

Launch the NetHunter app → open Kali Chroot → Kali terminal:

iw dev

Expected output:

phy#0
	Interface wlan0
		ifindex 3
		type managed

The interface is visible inside the chroot — this is the moment most OTG setups fail, so if you see wlan0 here, you are 90 % done.

Step 4: Monitor mode​

Inside the Kali terminal (you need root — NetHunter runs as root by default):

airmon-ng check kill
airmon-ng start wlan0
iwconfig

Expected output: wlan0mon appears with Mode:Monitor.

aireplay-ng --test wlan0mon

Expected output: 30/30: 100% and Injection is working!

What about Realtek chipsets?​

The RTL8812AU (AWUS036ACH) deserves an honest paragraph: it can work on NetHunter devices whose kernel includes a pre-built 8812au module (some community kernels do), but do not plan your course project around it. DKMS compilation inside the Android chroot fails on most phones because the phone kernel headers are absent. If your only adapter is Realtek, test on a laptop first — the Kali guide works there — and treat the phone as a bonus.

Common errors (FAQ)​

Error / symptomCauseFix
lsusb shows nothingOTG not in host mode / power issueUse a powered OTG hub; try another OTG cable; check the phone's "USB" notification
iw dev empty inside chrootInterface not yet created / wrong netnsRe-plug the adapter; check lsusb first; reboot phone and retry
airmon-ng says command not foundNetHunter chroot incompleteReinstall the chroot via the NetHunter app; apt update && apt install aircrack-ng
Adapter detected but stuck in managedPhone kernel lacks monitor support for that chipsetCheck the NetHunter supported devices list; switch to an in-kernel chipset adapter
MT7921AUN adapter not detected at allPhone kernel older than 5.18Use a newer NetHunter kernel image or a phone with a GKI 5.18+ kernel
WLAN dies under loadUSB power limits on phonePowered OTG hub; disable phone battery optimization for NetHunter

References​