# Building Custom Kernel Modules & Firmware

This module works out of the box for everything that's native to the Pixel 10 Pro Fold kernel.
Some features need extra firmware or kernel modules you build yourself.

## What's Already Native (No Build Needed)

| Component | Driver | Status |
|-----------|--------|--------|
| GPU | pvrsrvkm (PowerVR DXT-48-1536) | Built-in, Vulkan 1.4 / GLES 3.x / OpenCL 3.0 |
| WiFi | bcmdhd4390 (Broadcom BCM4390) | Built-in, Wi-Fi 7 / WFD R2 / P2P |
| Bluetooth | btqca + btbcm + rfcomm + hidp | Built-in |
| Xbox Controllers | xpad | Built-in (CONFIG_JOYSTICK_XPAD=y) |
| PS5 DualSense | hid-playstation | Built-in |
| PS4 DualShock | hid-sony | Built-in |
| Switch Pro / Joy-Con | hid-nintendo | Built-in |
| Xbox One (BT) | hid-microsoft | Built-in |
| Logitech (F310/F710) | hid-logitech + hidpp | Built-in |
| Steam Controller | hid-steam | Built-in |
| Wacom Tablets | wacom | Built-in |
| 8BitDo / Generic | hid-generic | Built-in |
| USB Audio | snd_usb_audio | Built-in |
| USB Serial (FTDI) | ftdi_sio | Built-in |
| USB CDC ACM | cdc_acm | Built-in |
| USB Cameras | uvcvideo | Built-in |
| WireGuard VPN | wireguard | Built-in |

## What Needs User Action

### 1. SDR Devices (RTL-SDR, HackRF, Airspy, LimeSDR)

**No kernel modules needed.** All SDR devices on Android use userspace USB libraries.
The module handles USB permissions automatically.

**RTL-SDR + HackRF Driver App (rtl_tcp_andro):**

This module includes the source for the Android RTL-SDR/HackRF driver app
([rtl_tcp_andro](https://github.com/signalwareltd/rtl_tcp_andro-.git)) as a
submodule in `tools/rtl_tcp_andro/`. It implements the rtl_tcp protocol natively
on Android via USB OTG — no root needed for the app itself.

To build the APK:
```bash
cd tools/rtl_tcp_andro
./gradlew assembleRelease
```

The APK will be at `app/build/outputs/apk/release/app-release-unsigned.apk`.
Copy it to `apk/rtl_tcp_andro.apk` and rebuild the module zip — the installer
will auto-install it on the device.

Or install directly:
```bash
adb install app/build/outputs/apk/release/app-release-unsigned.apk
```

The app provides an `iqsrc://` intent that any SDR client app can use to
receive I/Q samples from RTL-SDR, HackRF, or SDRplay hardware.

Supported hardware: RTL-SDR (all versions), HackRF One, SDRplay RSP

**Setup in Termux:**

```bash
pkg update && pkg install -y rtl-sdr hackrf
```

This gives you: `rtl_sdr`, `rtl_fm`, `rtl_adsb`, `rtl_power`, `rtl_tcp`, `hackrf_transfer`, `hackrf_sweep`

**Android apps that work with USB OTG SDR:**
- SDR Touch (RTL-SDR)
- RF Analyzer (RTL-SDR)
- Aerial TV (DVB-T via RTL-SDR)
- SDR++ (if compiled for Android via Termux)

**Switching between DVB-T and SDR:**
There's no kernel conflict on this device (no DVB modules compiled in).
Just use the appropriate app — Aerial TV for DVB-T, SDR Touch for scanning.

### 2. Nexmon WiFi Monitor/Injection Mode

The BCM4390 is a new chip. Nexmon does NOT officially support it yet.

**To check for support:**
```bash
git clone https://github.com/seemoo-lab/nexmon
grep -r "4390" nexmon/
```

**If/when BCM4390 patches become available:**

1. Clone nexmon and set up the build environment:
```bash
# In Termux or a Linux build machine
git clone https://github.com/seemoo-lab/nexmon
cd nexmon
source setup_env.sh
make
```

2. Build the patched firmware for BCM4390:
```bash
cd patches/bcm4390/<firmware_version>/nexmon
make
```

3. Copy the firmware files to the module:
```bash
# Monitor mode firmware
cp <built_firmware>.bin /data/adb/modules/driver-manager/firmware/fw_bcm4390_monitor.bin

# Injection mode firmware (if separate)
cp <built_firmware_inject>.bin /data/adb/modules/driver-manager/firmware/fw_bcm4390_injection.bin
```

4. Switch mode via WebUI or manually:
```bash
echo "monitor" > /data/adb/modules/driver-manager/config/wifi_mode
sh /data/adb/modules/driver-manager/service.sh
```

**Currently supported Broadcom chips with nexmon:**
BCM4330, BCM4335b0, BCM4339, BCM43430a1, BCM43439a0, BCM43451b1,
BCM43455c0, BCM43436b0, BCM4375b1, BCM4389c1, BCM4398d0

### 3. Joydev (/dev/input/jsX)

The kernel has `CONFIG_INPUT_JOYDEV` disabled. Most Android games use evdev
(`/dev/input/eventX`) which works fine. If you need joydev for a specific app:

**Option A: Build joydev.ko**

You need the kernel source matching your device's kernel version.

```bash
# Get kernel version
uname -r

# Clone the kernel source
# For Pixel 10 (rango), the source is in the Android kernel common tree
repo init -u https://android.googlesource.com/kernel/manifest -b android-gs-laguna-<version>
repo sync -c

# Build the module
make ARCH=arm64 modules_prepare
make ARCH=arm64 M=drivers/input/joydev modules
```

Copy `joydev.ko` to `/data/adb/modules/driver-manager/modules/` and it will
be loaded on next boot.

**Option B: Use a custom kernel** that has joydev compiled in.

### 4. GPU Driver Updates

The PowerVR GPU driver is updatable via Google Play (Game Update Pack).
This module sets `ro.gfx.driver.1` to request the updatable driver.

**To check current driver version:**
```bash
dumpsys gpu | grep -i version
# or
getprop ro.gfx.driver.1
```

**To force a specific driver version:**
If Google hasn't pushed v25.1+ yet, check:
- Settings > System > System Update (driver updates come with security patches)
- The Android 16 QPR3 update bumps the driver to v1.634.2906

### 5. OpenCL (CUDA Alternative)

There is no CUDA on Android (NVIDIA only). PowerVR supports OpenCL 3.0 instead.

**To use OpenCL on Pixel 10:**
- PowerVR OpenCL library: `/vendor/lib64/libPVROCL.so`
- Use compute mode in this module to enable FP16 and max GPU freq
- Vulkan compute shaders are also an option for GPU workloads

**Termux OpenCL setup:**
```bash
pkg install -y clinfo opencl-headers
clinfo  # Should show PowerVR device
```

## Kernel Module Loading via KernelSU

KernelSU supports loading `.ko` files. Place them in:
```
/data/adb/modules/driver-manager/modules/<name>.ko
```

The module will `insmod` any `.ko` files found at boot.

**Important:** Modules must be compiled against the exact kernel version
running on your device. Mismatched modules will fail to load with
"Invalid module format" or segfault.

Check your kernel version:
```bash
uname -r
cat /proc/version
```

## USB Device Reference

| Device | Vendor:Product | Type |
|--------|---------------|------|
| RTL-SDR v1 | 0bda:2832 | Userspace USB |
| RTL-SDR v3 | 0bda:2838 | Userspace USB |
| RTL-SDR v4 | 0bda:2840 | Userspace USB |
| HackRF One | 1d50:6089 | Userspace USB |
| Airspy Mini | 1d50:60a1 | Userspace USB |
| Airspy HF+ | 1d50:6108 | Userspace USB |
| LimeSDR Mini | 04b4:00f3 | Userspace USB |
| SDRplay RSP1 | 1df7:2500 | Userspace USB |
| SDRplay RSP2 | 1df7:3020 | Userspace USB |
| Xbox Controller | 045e:028e | Native xpad |
| PS5 DualSense | 054c:0ce6 | Native hid-playstation |
| PS4 DualShock | 054c:09cc | Native hid-sony |
| Switch Pro | 057e:2009 | Native hid-nintendo |
| 8BitDo | Various | Native hid-generic |