### Example extlinux.conf Configuration

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/boot.md

A sample configuration file for defining boot entries. Unsupported directives are ignored by lk2nd.

```text
timeout 1
menu title Boot the OS
default MyOS

# Bootloader should pick the DT
label MyOS
    linux /vmlinuz
    initrd /initramfs
    fdtdir /dtbs
    append earlycon console=ttyMSM0,115200
```

--------------------------------

### Build lk2nd from Source

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Steps to install dependencies and compile lk2nd for specific Qualcomm SoC targets.

```bash
# Install build requirements (Debian/Ubuntu)
sudo apt install gcc-arm-none-eabi device-tree-compiler libfdt-dev python3

# Build for MSM8916 devices (e.g., Samsung Galaxy A3, Xiaomi Redmi 2)
make TOOLCHAIN_PREFIX=arm-none-eabi- lk2nd-msm8916

# Build for MSM8974 devices (e.g., OnePlus One, Nexus 5)
make TOOLCHAIN_PREFIX=arm-none-eabi- lk2nd-msm8974

# Build for MSM8953 devices (e.g., Xiaomi Mi A1, Motorola G5 Plus)
make TOOLCHAIN_PREFIX=arm-none-eabi- lk2nd-msm8953

# Output image location
ls build-lk2nd-msm8916/lk2nd.img
```

--------------------------------

### Root Node Example

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

The root node contains information for the previous bootloader, typically including msm-id and board-id. lk2nd generally does not use this data.

```dts
/ {
	qcom,msm-id = <QCOM_ID_MSM8916 0>;
	qcom,board-id = <0xCE08FF01 1>, <0xCE08FF01 3>, <0xCE08FF01 7>;
};

```

--------------------------------

### lk2nd Kernel Command Line Arguments

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Configure lk2nd boot behavior using specific kernel command line arguments. These arguments are passed from the OS being booted. Examples include enabling simplefb, ramoops, and spin table configuration.

```ini
# extlinux.conf with lk2nd-specific arguments

label mainline
    linux /vmlinuz
    initrd /initramfs
    fdtdir /dtbs
    append earlycon console=ttyMSM0,115200 lk2nd.pass-simplefb=xrgb8888,autorefresh,relocate lk2nd.pass-ramoops

# Available lk2nd cmdline arguments:
#
# lk2nd.pass-simplefb           - Add simplefb node to device tree
# lk2nd.pass-simplefb=autorefresh  - Enable display autorefresh for command mode panels
# lk2nd.pass-simplefb=xrgb8888     - Set display mode to XRGB8888
# lk2nd.pass-simplefb=rgb565       - Set display mode to RGB565
# lk2nd.pass-simplefb=relocate     - Relocate framebuffer to safe region
# lk2nd.pass-simplefb=xrgb8888,autorefresh,relocate  - Combine options
#
# lk2nd.pass-ramoops             - Add ramoops node to device tree
# lk2nd.pass-ramoops=zap         - Clear ramoops region before booting
#
# lk2nd.spin-table=force         - Force spintable even if PSCI available
```

--------------------------------

### Remap Keys using GPIO Keys in lk2nd

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Remap keys for menu navigation when default keys are unavailable. This example unmaps KEY_VOLUMEUP and re-maps it to KEY_POWER.

```dts
	gpio-keys {
		compatible = "gpio-keys";

		/* HACK: map KEY_VOLUMEUP to non-existent button so the actual
		 * Volume Up button will successfully re-map to KEY_POWER below.
		 */
		volume-up-unmap {
			lk2nd,code = <KEY_VOLUMEUP>;
			gpios = <&pmic_pon 0 0>;
		};

		/*
		 * Remap Volume Up to KEY_POWER to allow selecting menu items as
		 * there is no power button present on the device.
		 * Use Volume Down to navigate the menu and Volume Up to select.
		 */
		volume-up {
			lk2nd,code = <KEY_POWER>;
			gpios = <&tlmm 85 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
		};
	};
```

--------------------------------

### Boot via Fastboot

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/boot.md

Use the fastboot interface to boot an OS image over USB.

```bash
fastboot boot boot.img
```

--------------------------------

### Create and Flash Android Boot Image

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Use mkbootimg to create a standard Android boot image and fastboot to flash or boot it. lk2nd automatically applies a 512K offset when flashing.

```bash
mkbootimg \
    --kernel zImage \
    --ramdisk initramfs.cpio.gz \
    --cmdline "console=ttyMSM0,115200 earlycon" \
    --base 0x80000000 \
    --pagesize 2048 \
    --output boot.img
```

```bash
fastboot flash boot boot.img
```

```bash
fastboot boot boot.img
```

--------------------------------

### Configure Boot Options with extlinux.conf

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

lk2nd supports extlinux.conf for boot configuration, similar to U-Boot. The file must be on an ext2 partition at /extlinux/extlinux.conf. It allows specifying kernel, initrd, DTB, and kernel command line arguments.

```ini
# /extlinux/extlinux.conf
# lk2nd searches partitions >16MiB and the boot partition (with 512K offset)

timeout 1
menu title Boot the OS
default postmarketos

label postmarketos
    linux /vmlinuz
    initrd /initramfs
    fdtdir /dtbs
    append earlycon console=ttyMSM0,115200 lk2nd.pass-simplefb

label recovery
    linux /vmlinuz-recovery
    initrd /initramfs-recovery
    fdt /dtbs/qcom-msm8916-samsung-a3u-eur.dtb
    append earlycon console=ttyMSM0,115200 rescue

# Supported commands:
# label <name>        - Start new boot entry
# default <name>      - Set default boot label
# linux <path>        - Kernel image path (alt: kernel)
# initrd <path>       - Initramfs path
# fdt <path>          - Device tree path (alt: devicetree)
# fdtdir <dir>        - Auto-find device tree directory (alt: devicetreedir)
# append <cmdline>    - Kernel command line
# fdtoverlays <files> - Space-separated DT overlay list (alt: devicetree-overlay)
```

--------------------------------

### Configure lk2nd Build Options

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Compile-time flags for customizing debugging, versioning, and signing of the boot image.

```bash
# Enable verbose logging to display (useful for debugging)
make TOOLCHAIN_PREFIX=arm-none-eabi- DEBUG=2 DEBUG_FBCON=1 lk2nd-msm8916

# Force boot into fastboot menu (for development)
make TOOLCHAIN_PREFIX=arm-none-eabi- LK2ND_FORCE_FASTBOOT=1 lk2nd-msm8916

# Override version string (for packaging)
make TOOLCHAIN_PREFIX=arm-none-eabi- LK2ND_VERSION="1.0.0-custom" lk2nd-msm8916

# Add delay before fastboot boot (for UART debugging)
make TOOLCHAIN_PREFIX=arm-none-eabi- LK2ND_FASTBOOT_DELAY=5000 lk2nd-msm8916

# Build only specific device tree files
make TOOLCHAIN_PREFIX=arm-none-eabi- LK2ND_DTBS="msm8916-samsung-a3" lk2nd-msm8916

# Sign the boot image for AVB1 (Android Verified Boot)
make TOOLCHAIN_PREFIX=arm-none-eabi- SIGN_BOOTIMG=1 lk2nd-msm8916

# Sign with custom keys (X.509 PEM cert and PKCS#8 key)
make TOOLCHAIN_PREFIX=arm-none-eabi- SIGN_BOOTIMG=1 \
    BOOTIMG_CERT=/path/to/cert.pem \
    BOOTIMG_KEY=/path/to/key.pk8 \
    lk2nd-msm8916
```

--------------------------------

### Configure GPIO Keys

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Define or remap physical buttons for navigation and boot menu interaction.

```c
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/input/input.h>

&lk2nd {
    device {
        // Standard GPIO key configuration
        gpio-keys {
            compatible = "gpio-keys";

            volume-down {
                lk2nd,code = <KEY_VOLUMEDOWN>;
                gpios = <&tlmm 81 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
            };

            volume-up {
                lk2nd,code = <KEY_VOLUMEUP>;
                gpios = <&tlmm 85 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
            };

            home {
                lk2nd,code = <KEY_HOME>;
                gpios = <&pmic 3 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
            };
        };
    };
};

// Remap Volume Up to Power key (for devices without power button)
&lk2nd {
    device {
        // Custom key hint for boot menu
        lk2nd,menu-key-strings = "Volume Down", "Volume Up";

        gpio-keys {
            compatible = "gpio-keys";

            // Unmap original Volume Up to non-existent GPIO
            volume-up-unmap {
                lk2nd,code = <KEY_VOLUMEUP>;
                gpios = <&pmic_pon 0 0>;
            };

            // Remap actual Volume Up button to Power key for menu selection
            volume-up {
                lk2nd,code = <KEY_POWER>;
                gpios = <&tlmm 85 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
            };
        };
    };
};
```

--------------------------------

### Build Target Mapping and Compilation

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Maps lk2nd build targets to supported Qualcomm SoCs and provides the command to initiate a build.

```bash
# Build target to SoC mapping:
#
# lk2nd-msm8916  -> MSM8916, MSM8939, MSM8929, MSM8936, APQ8016, etc.
# lk2nd-msm8909  -> MSM8909, MDM9209, MDM9609, APQ8009
# lk2nd-msm8226  -> MSM8226, MSM8926, MSM8626, APQ8026, etc.
# lk2nd-msm8610  -> MSM8610, MSM8212, MSM8110
# lk2nd-msm8952  -> MSM8952, MSM8956, MSM8976, MSM8937, MSM8917
# lk2nd-msm8953  -> MSM8953, APQ8053
# lk2nd-msm8960  -> MSM8960, MSM8930, APQ8064, MSM8660
# lk2nd-msm8974  -> MSM8974, MSM8674, APQ8074
# lk2nd-msm8994  -> MSM8994, MSM8992, APQ8094
# lk2nd-msm8996  -> MSM8996, APQ8096
# lk2nd-msm8660  -> MSM8660
# lk2nd-apq8084  -> APQ8084
# lk2nd-mdm9607  -> MDM9607
# lk2nd-mdm9640  -> MDM9640

# Check your device's SoC and use the corresponding target
make TOOLCHAIN_PREFIX=arm-none-eabi- lk2nd-msm8916
```

--------------------------------

### Flash Actual Boot Image

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/README.md

This command flashes the main boot image, ensuring it's offset by 512 KiB to avoid overwriting lk2nd.

```bash
fastboot flash boot boot.img
```

--------------------------------

### Build lk2nd image

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/building.md

Execute the make command to build the lk2nd image for a specific SoC target.

```bash
$ make TOOLCHAIN_PREFIX=arm-none-eabi- lk2nd-msmXXXX
```

--------------------------------

### Execute Fastboot OEM Commands

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Standard and custom OEM commands for device debugging, memory inspection, and state management.

```bash
# Enter fastboot mode: Press Volume Down while booting
# Enter recovery mode: Press Volume Up while booting

# Flash an operating system boot image (with 512K offset to preserve lk2nd)
fastboot flash boot boot.img

# Update lk2nd itself
fastboot flash lk2nd lk2nd.img

# Boot an image without flashing
fastboot boot boot.img

# Get lk2nd debug log
fastboot oem log && fastboot get_staged output.txt
# Or output directly to terminal
fastboot oem log && fastboot get_staged /dev/stdout

# Stage and retrieve device tree blob
fastboot oem dtb && fastboot get_staged dtb.bin

# Take a screenshot of the bootloader display
fastboot oem screenshot && fastboot get_staged screenshot.bin

# Reboot into EDL (Emergency Download) mode
fastboot oem reboot-edl

# Debug commands - dump CPUID registers
fastboot oem debug cpuid

# Debug commands - read/write memory (peek/poke)
fastboot oem debug readl 0x01234000   # Read 32-bit value
fastboot oem debug writel 0x01234000 0xDEADBEEF   # Write 32-bit value

# Dump regulator states
fastboot oem debug spmi-regulators

# List available OEM commands
fastboot oem help
```

--------------------------------

### Flash lk2nd.img using Fastboot

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/README.md

Use this command to flash the lk2nd bootloader image onto the boot partition via fastboot.

```bash
fastboot flash boot lk2nd.img
```

--------------------------------

### Workaround for Fastboot Partition Size Error

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/README.md

If encountering 'fastboot: error: Couldn't parse partition size '0x'', try these alternative flashing methods.

```bash
fastboot flash:raw boot lk2nd.img
```

```bash
fastboot boot lk2nd.img
fastboot flash lk2nd lk2nd.img
```

--------------------------------

### Configure Display Panel Selection

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Set up automatic panel detection using compatible strings or ADC ranges for Sony devices.

```c
// Standard panel configuration
&lk2nd {
    device {
        panel {
            compatible = "wingtech,wt88047-panel", "lk2nd,panel";

            qcom,mdss_dsi_r69431_720p_video {
                compatible = "wingtech,sharp-r69431";
            };
            qcom,mdss_dsi_nt35521_720p_video {
                compatible = "wingtech,auo-nt35521";
            };
            qcom,mdss_dsi_otm1285a_720p_video {
                compatible = "wingtech,boe-otm1285a";
            };
        };
    };
};

// Sony devices using lcdid_adc ranges
&lk2nd {
    device {
        panel {
            compatible = "sony,aries-panel", "lk2nd,panel";

            novatek_jdi_720p_cmd {
                compatible = "sony,novatek-jdi-720p-cmd";
                sony,lcd-id-adc = <0x109618 0x12c898>;  // min, max ADC range
            };

            novatek_sharp_720p_cmd {
                compatible = "sony,novatek-sharp-720p-cmd";
                sony,lcd-id-adc = <0x562e8 0x65130>;
            };
        };
    };
};
```

--------------------------------

### Configure Special Device Options

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Sets navigation hints, SD card slot mapping, and downstream compatibility IDs for specific hardware.

```c
&lk2nd {
    // Smartwatch with single button navigation
    watch {
        model = "LG G Watch R";
        compatible = "lg,lenok";

        // Enable single key navigation (short/long press)
        lk2nd,single-key-navigation;

        // Custom menu navigation hint
        lk2nd,menu-key-strings = "Short Press", "Long Press";
    };

    // Device with non-standard SD card slot
    device {
        model = "Some MSM8974 Device";
        compatible = "vendor,device";

        // SD card on slot 3 instead of default slot 2
        lk2nd,sd-mmc = <&sdhc3>;  // Available: sdhc2, sdhc3
    };

    // Override MSM/board ID for downstream kernel compatibility
    downstream-compat {
        model = "Device with custom IDs";

        qcom,msm-id = <QCOM_ID_MSM8916 0>;
        qcom,board-id = <0xCE08FF01 1>;
    };
};
```

--------------------------------

### Configure lk2nd Device Matching

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Define device identification rules using bootloader versions, device names, command line substrings, or display panel detection.

```c
&lk2nd {
    a3lte {
        model = "Samsung Galaxy A3 (SM-A300F)";
        lk2nd,match-bootloader = "A300F*";
    };
};

// Match by device name (android.device= cmdline argument)
&lk2nd {
    victara {
        model = "Motorola Moto X 2014";
        lk2nd,match-device = "victara";
    };
};

// Match by any cmdline substring
&lk2nd {
    lenok {
        model = "LG G Watch R";
        lk2nd,match-cmdline = "*lenok*";
    };
};

// Match by detected display panel
&lk2nd {
    device {
        model = "Xiaomi Redmi 2";
        lk2nd,match-panel;

        panel {
            compatible = "wingtech,wt88047-panel", "lk2nd,panel";

            qcom,mdss_dsi_r69431_720p_video {
                compatible = "wingtech,sharp-r69431";
            };
            qcom,mdss_dsi_nt35521_720p_video {
                compatible = "wingtech,auo-nt35521";
            };
        };
    };
};
```

--------------------------------

### Flash lk2nd.img using EDL

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/README.md

Flash the lk2nd bootloader image using the Emergency Download (EDL) mode.

```bash
edl w boot lk2nd.img
```

--------------------------------

### Match Cmdline Property

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

This property checks the entire command line for a match against a given expression, similar to 'match-bootloader' but broader in scope.

```dts
	lk2nd,match-cmdline = "*lenok*";

```

--------------------------------

### Customize lk2nd Menu Navigation Key Hint

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Customize the hint shown in the lk2nd boot menu for re-mapped keys. Specify strings for navigation and selection.

```dts
	lk2nd,menu-key-strings = "Volume Down", "Volume Up";
```

--------------------------------

### Match Device Property

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

This property matches the 'android.device=' argument from the previous bootloader's command line with a specified device name.

```dts
	lk2nd,match-device = "victara";

```

--------------------------------

### Device Tree Configuration for lk2nd

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Configure per-device settings in lk2nd device tree source files (.dts). Each device node specifies model, compatible strings, and device-specific properties, including matching by bootloader version.

```c
// lk2nd/device/dts/msm8916/msm8916-samsung-a3u-eur.dts

#include <skeleton64.dtsi>
#include <lk2nd.dtsi>

/ {
    // Root node: information for stock bootloader
    qcom,msm-id = <QCOM_ID_MSM8916 0>;
    qcom,board-id = <0xCE08FF01 1>, <0xCE08FF01 3>, <0xCE08FF01 7>;
};

&lk2nd {
    // Single device in this DT file
    a3lte {
        model = "Samsung Galaxy A3 (SM-A300F)";
        compatible = "samsung,a3u-eur", "samsung,a3";
        lk2nd,dtb-files = "msm8916-samsung-a3u-eur";

        // Match device by bootloader version string
        lk2nd,match-bootloader = "A300F*";
    };
};

// Multiple devices sharing one DT file
&lk2nd {
    a3lte {
        model = "Samsung Galaxy A3 (SM-A300F)";
        compatible = "samsung,a3u-eur";
        lk2nd,match-bootloader = "A300F*";
        lk2nd,dtb-files = "msm8916-samsung-a3u-eur";
    };

    a5lte {
        model = "Samsung Galaxy A5 (SM-A500F)";
        compatible = "samsung,a5u-eur";
        lk2nd,match-bootloader = "A500F*";
        lk2nd,dtb-files = "msm8916-samsung-a5u-eur";
    };
};

// Single device with properties at lk2nd level
&lk2nd {
    model = "Huawei Y635-L01";
    compatible = "huawei,y635";
    lk2nd,dtb-files = "msm8916-huawei-y635";
};
```

--------------------------------

### Configure GPIO and Regulator Drivers

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Defines GPIO-based LEDs and fixed/LDO regulators within the lk2nd device tree node.

```c
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/lk2nd/regulator.h>

&lk2nd {
    device {
        // GPIO LED control (mainly for lk1st)
        gpio-leds {
            compatible = "gpio-leds";

            red {
                gpios = <&tlmm 3 GPIO_ACTIVE_HIGH>;
                default-state = "on";
            };

            green {
                gpios = <&tlmm 4 GPIO_ACTIVE_HIGH>
                default-state = "off";
            };

            blue {
                gpios = <&tlmm 5 GPIO_ACTIVE_HIGH>;
                default-state = "off";
            };
        };

        // Fixed regulator for panel/backlight power
        regulator-backlight {
            compatible = "regulator-fixed";
            gpios = <&tlmm 9 GPIO_ACTIVE_HIGH>;
        };

        regulator-panel {
            compatible = "regulator-fixed";
            gpios = <&tlmm 10 GPIO_ACTIVE_HIGH>;
        };

        // LDO regulator enable
        regulator-l11 {
            compatible = "regulator-ldo";
            id = <REG_LDO11>;
        };
    };
};
```

--------------------------------

### Flash lk2nd to Device

Source: https://context7.com/msm8916-mainline/lk2nd/llms.txt

Commands to flash the lk2nd image using various device-specific interfaces.

```bash
# Flash using Fastboot (most Android devices)
fastboot flash boot lk2nd.img

# Flash using Heimdall (Samsung devices)
heimdall flash --BOOT lk2nd.img

# Flash using EDL (Emergency Download mode)
edl w boot lk2nd.img

# Workaround for partition size parsing errors
fastboot flash:raw boot lk2nd.img
# Or boot first, then flash
fastboot boot lk2nd.img
fastboot flash lk2nd lk2nd.img
```

--------------------------------

### Device Node with Model and Compatible Properties

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Every device node should specify its marketing name in the 'model' property and a list of compatible values. The 'lk2nd,dtb-files' property can list possible device-tree names for the device.

```dts
	gt58lte {
		model = "Samsung Galaxy Tab A 8.0 (LTE, SM-T355)";
		compatible = "samsung,gt58lte", "samsung,gt58";
		lk2nd,dtb-files = "msm8916-samsung-gt58";
	};

```

--------------------------------

### Build lk2nd

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/README.md

General command to build lk2nd for a specific MSM target using a specified toolchain prefix. Refer to building.md for more details.

```bash
make TOOLCHAIN_PREFIX=arm-none-eabi- lk2nd-msmXXXX
```

--------------------------------

### Flash lk2nd.img using Heimdall

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/README.md

Flash the lk2nd bootloader image using the heimdall tool, commonly used for Samsung devices.

```bash
heimdall flash --BOOT lk2nd.img
```

--------------------------------

### Match Panel Property

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

When no suitable command-line parameter is available for matching, this property can be used with a list of possible display panels to determine the device.

```dts
	lk2nd,match-panel;
	panel { /* ... */ };

```

--------------------------------

### Retrieve lk2nd Log File

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/README.md

Use these fastboot commands to retrieve a log file from lk2nd for debugging purposes. The output can be directed to a file or standard output.

```bash
fastboot oem log && fastboot get_staged <output-file>
```

--------------------------------

### Match Bootloader Property

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

This property allows lk2nd to match the 'android.bootloader=' argument from the previous bootloader's command line with a specified expression.

```dts
	lk2nd,match-bootloader = "A300F*";

```

--------------------------------

### Panel Selection with Compatible Values

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

This section lists possible display panels and their compatible values. lk2nd can patch the device-tree to insert the compatible value for the detected display.

```dts
	panel {
		compatible = "wingtech,wt88047-panel", "lk2nd,panel";

		qcom,mdss_dsi_r69431_720p_video {
			compatible = "wingtech,sharp-r69431";
		};
		qcom,mdss_dsi_nt35521_720p_video {
			compatible = "wingtech,auo-nt35521";
		};
		/* ... */
	};

```

--------------------------------

### Configure GPIO LEDs in lk2nd

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Configure GPIO LEDs in lk2nd. Supports 'gpios' and 'default-state'. Primarily for lk1st compatibility and debugging.

```dts
gpio-leds {
    compatible = "gpio-leds";

    red {
        gpios = <&tlmm 3 GPIO_ACTIVE_HIGH>;
        default-state = "on";
    };

    green {
        gpios = <&tlmm 4 GPIO_ACTIVE_HIGH>;
        default-state = "off";
    };
};
```

--------------------------------

### Update lk2nd Directly

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/README.md

Update the lk2nd bootloader itself by flashing 'lk2nd.img' from within the lk2nd fastboot interface.

```bash
fastboot flash lk2nd lk2nd.img
```

--------------------------------

### Policy Definitions (set-policy)

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Specifies policy definitions (set-policy), including the root policy.

```APIDOC
## Policy Definitions (set-policy)

### Description
Specifies policy definitions (set-policy).

### Parameters
- **set-policy** (integer) - Identifier for the policy.

### Example
```
set-policy 0 : set-policy-root
```
```

--------------------------------

### Content Type Definitions (set-ctype)

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Provides a comprehensive list of content type definitions (set-ctype) used in various transaction and security contexts.

```APIDOC
## Content Type Definitions (set-ctype)

### Description
Provides a comprehensive list of content type definitions (set-ctype).

### Parameters
- **set-ctype** (integer) - Identifier for the content type.

### Example
```
set-ctype 0 : setct-PANData
set-ctype 1 : setct-PANToken
```
```

--------------------------------

### Configure Fixed Regulator in lk2nd

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Configure a fixed regulator in lk2nd, primarily for panel and backlight power. Supports 'gpios'. Useful for lk1st consistency.

```dts
regulator-backlight {
    compatible = "regulator-fixed";
    gpios = <&tlmm 9 GPIO_ACTIVE_HIGH>;
};
```

--------------------------------

### Certificate Extension Definitions (setCext)

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Details certificate extensions (setCext) used for various certificate attributes and capabilities.

```APIDOC
## Certificate Extension Definitions (setCext)

### Description
Details certificate extensions (setCext) used for various certificate attributes and capabilities.

### Parameters
- **setCext** (integer) - Identifier for the certificate extension.

### Example
```
set-certExt 0 : setCext-hashedRoot
set-certExt 1 : setCext-certType
```
```

--------------------------------

### Configure GPIO Keys for lk2nd

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Define GPIO keys for lk2nd, overriding default keymaps. Supports custom keycodes using 'lk2nd,code' and GPIO mapping.

```dts
	gpio-keys {
		compatible = "gpio-keys";

		volume-down {
			lk2nd,code = <KEY_VOLUMEDOWN>;
			gpios = <&tlmm 81 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
		};
		home {
			lk2nd,code = <KEY_HOME>;
			gpios = <&pmic 3 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
		};
	};
```

--------------------------------

### X.500 Directory Services

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Defines structures and attributes related to X.500 directory services.

```APIDOC
## X.500 Directory Services

### Description
Defines structures and attributes related to X.500 directory services.

### Endpoints
- `X500` (ID: 2 5): directory services (X.500)
  - `X509` (ID: 4)
    - `CN` (ID: 3): commonName
    - `SN` (ID: 4): surname
    - `serialNumber` (ID: 5)
    - `C` (ID: 6): countryName
    - `L` (ID: 7): localityName
    - `ST` (ID: 8): stateOrProvinceName
    - `street` (ID: 9): streetAddress
    - `O` (ID: 10): organizationName
    - `OU` (ID: 11): organizationalUnitName
    - `title` (ID: 12): title
    - `description` (ID: 13)
    - `searchGuide` (ID: 14)
    - `businessCategory` (ID: 15)
    - `postalAddress` (ID: 16)
    - `postalCode` (ID: 17)
    - `postOfficeBox` (ID: 18)
    - `physicalDeliveryOfficeName` (ID: 19)
    - `telephoneNumber` (ID: 20)
    - `telexNumber` (ID: 21)
    - `teletexTerminalIdentifier` (ID: 22)
    - `facsimileTelephoneNumber` (ID: 23)
    - `x121Address` (ID: 24)
    - `internationaliSDNNumber` (ID: 25)
    - `registeredAddress` (ID: 26)
    - `destinationIndicator` (ID: 27)
    - `preferredDeliveryMethod` (ID: 28)
    - `presentationAddress` (ID: 29)
    - `supportedApplicationContext` (ID: 30)
    - `member` (ID: 31)
    - `owner` (ID: 32)
    - `roleOccupant` (ID: 33)
    - `seeAlso` (ID: 34)
    - `userPassword` (ID: 35)
    - `userCertificate` (ID: 36)
    - `cACertificate` (ID: 37)
    - `authorityRevocationList` (ID: 38)
    - `certificateRevocationList` (ID: 39)
    - `crossCertificatePair` (ID: 40)
    - `name` (ID: 41): name
    - `GN` (ID: 42): givenName
    - `initials` (ID: 43): initials
    - `generationQualifier` (ID: 44)
    - `x500UniqueIdentifier` (ID: 45)
    - `dnQualifier` (ID: 46): dnQualifier
    - `enhancedSearchGuide` (ID: 47)
    - `protocolInformation` (ID: 48)
    - `distinguishedName` (ID: 49)
    - `uniqueMember` (ID: 50)
    - `houseIdentifier` (ID: 51)
    - `supportedAlgorithms` (ID: 52)
    - `deltaRevocationList` (ID: 53)
    - `dmdName` (ID: 54)
    - `pseudonym` (ID: 65)
    - `role` (ID: 72): role
  - `X500algorithms` (ID: 8): directory services - algorithms
    - `RSA` (ID: 1 1): rsa
    - `RSA-MDC2` (ID: 3 100): mdc2WithRSA
    - `MDC2` (ID: 3 101): mdc2
  - `id-ce` (ID: 29)
    - `subjectDirectoryAttributes` (ID: 9): X509v3 Subject Directory Attributes
    - `subjectKeyIdentifier` (ID: 14): X509v3 Subject Key Identifier
    - `keyUsage` (ID: 15): X509v3 Key Usage
    - `privateKeyUsagePeriod` (ID: 16): X509v3 Private Key Usage Period
    - `subjectAltName` (ID: 17): X509v3 Subject Alternative Name
    - `issuerAltName` (ID: 18): X509v3 Issuer Alternative Name
    - `basicConstraints` (ID: 19): X509v3 Basic Constraints
    - `crlNumber` (ID: 20): X509v3 CRL Number
    - `CRLReason` (ID: 21): X509v3 CRL Reason Code
    - `invalidityDate` (ID: 24): Invalidity Date
    - `deltaCRL` (ID: 27): X509v3 Delta CRL Indicator
    - `issuingDistributionPoint` (ID: 28)
```

--------------------------------

### Attribute Definitions (setAttr)

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Defines general attributes (setAttr) such as certificate types, payment gateway capabilities, and token types.

```APIDOC
## Attribute Definitions (setAttr)

### Description
Defines general attributes (setAttr).

### Parameters
- **setAttr** (integer) - Identifier for the attribute.

### Example
```
set-attr 0 : setAttr-Cert
set-attr 1 : setAttr-PGWYcap : payment gateway capabilities
```
```

--------------------------------

### Specific Attribute Definitions

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Provides specific definitions for attributes like Certificate attributes, Token Types, and Issuer Capabilities.

```APIDOC
## Specific Attribute Definitions

### Description
Provides specific definitions for attributes.

### Parameters
- **setAttr-Cert** (integer) - Identifier for Certificate attributes.
- **setAttr-TokenType** (integer) - Identifier for Token Type attributes.
- **setAttr-IssCap** (integer) - Identifier for Issuer Capability attributes.

### Example
```
setAttr-Cert 0 : set-rootKeyThumb
setAttr-TokenType 1 : setAttr-Token-EMV
setAttr-IssCap 3 : setAttr-IssCap-CVM
```
```

--------------------------------

### Access Descriptors (ad)

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Defines various access descriptors used for certificate extensions.

```APIDOC
## Access Descriptors (ad)

### Description
Defines various access descriptors used for certificate extensions.

### Endpoints
- `ad-OCSP` (ID: 1): OCSP
- `ad-ca-issuers` (ID: 2): CA Issuers
- `ad-timeStamping` (ID: 3): AD Time Stamping
- `ad-dvcs` (ID: 4): AD DVCS
- `caRepository` (ID: 5): CA Repository
```

--------------------------------

### PKIX OCSP Definitions

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Defines components and types related to the Online Certificate Status Protocol (OCSP).

```APIDOC
## PKIX OCSP Definitions

### Description
Defines components and types related to the Online Certificate Status Protocol (OCSP).

### Endpoints
- `basicOCSPResponse` (ID: 1): Basic OCSP Response
- `Nonce` (ID: 2): OCSP Nonce
- `CrlID` (ID: 3): OCSP CRL ID
- `acceptableResponses` (ID: 4): Acceptable OCSP Responses
- `noCheck` (ID: 5): OCSP No Check
- `archiveCutoff` (ID: 6): OCSP Archive Cutoff
- `serviceLocator` (ID: 7): OCSP Service Locator
- `extendedStatus` (ID: 8): Extended OCSP Status
- `valid` (ID: 9)
- `path` (ID: 10)
- `trustRoot` (ID: 11): Trust Root
```

--------------------------------

### Configure LDO Regulator in lk2nd

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Configure an LDO regulator in lk2nd. This driver is simple and only enables the selected regulator using its ID.

```dts
#include <dt-bindings/lk2nd/regulator.h>

regulator-l11 {
    compatible = "regulator-ldo";
    id = <REG_LDO11>;
};
```

--------------------------------

### Single-Key Navigation Property

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Enables a single-key navigation scheme for devices with only one physical button, utilizing short and long presses for different actions.

```dts
	lk2nd,single-key-navigation;

```

--------------------------------

### Message Extension Definitions (set-msgExt)

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Defines message extensions (set-msgExt) used for various cryptographic and authentication purposes.

```APIDOC
## Message Extension Definitions (set-msgExt)

### Description
Defines message extensions (set-msgExt) used for various cryptographic and authentication purposes.

### Parameters
- **set-msgExt** (integer) - Identifier for the message extension.

### Example
```
set-msgExt 1 : setext-genCrypt : generic cryptogram
set-msgExt 3 : setext-miAuth : merchant initiated auth
```
```

--------------------------------

### Algorithm Identifiers

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Lists various algorithm identifiers used in cryptographic operations.

```APIDOC
## Algorithm Identifiers

### Description
Lists various algorithm identifiers used in cryptographic operations.

### Endpoints
- `algorithm` (ID: 1 3 14 3 2): algorithm
  - `RSA-NP-MD5` (ID: 3): md5WithRSA
  - `DES-ECB` (ID: 6): des-ecb
  - `DES-CBC` (ID: 7): des-cbc
  - `DES-OFB` (ID: 8): des-ofb
  - `DES-CFB` (ID: 9): des-cfb
  - `rsaSignature` (ID: 11)
  - `DSA-old` (ID: 12): dsaEncryption-old
  - `DSA-SHA` (ID: 13): dsaWithSHA
  - `RSA-SHA` (ID: 15): shaWithRSAEncryption
  - `DES-EDE` (ID: 17): des-ede
  - `DES-EDE3` (ID: 17): des-ede3
  - `DES-EDE-CBC` (ID: 17): des-ede-cbc
  - `DES-EDE-CFB` (ID: 17): des-ede-cfb
  - `DES-EDE3-CFB` (ID: 17): des-ede3-cfb
  - `DES-EDE-OFB` (ID: 17): des-ede-ofb
  - `DES-EDE3-OFB` (ID: 17): des-ede3-ofb
  - `DESX-CBC` (ID: 17): desx-cbc
  - `SHA` (ID: 18): sha
  - `SHA1` (ID: 26): sha1
  - `DSA-SHA1-old` (ID: 27): dsaWithSHA1-old
  - `RSA-SHA1-2` (ID: 29): sha1WithRSA
- `RIPEMD160` (ID: 1 3 36 3 2): ripemd160
- `RSA-RIPEMD160` (ID: 1 3 36 3 3 1 2): ripemd160WithRSA
- `SXNetID` (ID: 1 3 101 1 4 1): Strong Extranet ID
```

--------------------------------

### ID Set Definitions

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Details the various types of identifier sets (id-set) and their specific meanings, including content types, message extensions, and certificate extensions.

```APIDOC
## ID Set Definitions

### Description
Details the various types of identifier sets (id-set) and their specific meanings.

### Parameters
- **id-set** (integer) - Identifier for the set.
- **set-ctype** (string) - Content types within the set.
- **set-msgExt** (string) - Message extensions within the set.
- **set-attr** (string) - Attributes within the set.
- **set-policy** (string) - Policy information within the set.
- **set-certExt** (string) - Certificate extensions within the set.

### Example
```
id-set 0 : set-ctype : content types
id-set 1 : set-msgExt : message extensions
```
```

--------------------------------

### Specify SD MMC Card Slot in lk2nd

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

Configure the SD MMC card slot for lk2nd if it differs from the default. This is applicable to platforms like msm8974 and is required for SD card boot.

```dts
	lk2nd,sd-mmc = <&sdhc3>;
```

--------------------------------

### lk2nd Node with Device Subnodes

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

The lk2nd node contains device-specific information. Each supported device is listed in a dedicated subnode. If only one device is supported, its information can be placed directly in the top-level lk2nd node.

```dts
&lk2nd {
	a3lte {
		model = "Samsung Galaxy A3 (SM-A300F)";
		/* ... */
	};

	gt58lte { /* ... */ };
};

```

```dts
&lk2nd {
	model = "Huawei Y635-L01";
	/* ... */
};

```

--------------------------------

### Sony Panel Selection with lcd-id-adc

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

For some Sony devices, panel selection is based on the 'sony,lcd-id-adc' property, which defines a range of values to identify the panel.

```dts
	panel {
		compatible = "sony,aries-panel", "lk2nd,panel";

		novatek_jdi_720p_cmd {
			compatible = "sony,novatek-jdi-720p-cmd";
			sony,lcd-id-adc = <0x109618 0x12c898>;
		};

		novatek_sharp_720p_cmd {
			compatible = "sony,novatek-sharp-720p-cmd";
			sony,lcd-id-adc = <0x562e8 0x65130>;
		};
	};

```

--------------------------------

### Pilot Attribute Types

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Defines various pilot attribute types used within the system, including organizational status, mail preferences, and security-related attributes.

```APIDOC
## Pilot Attribute Types

### Description
Defines various pilot attribute types used within the system.

### Parameters
- **pilotAttributeType** (integer) - Description of the attribute type.

### Example
```
pilotAttributeType 45 : : organizationalStatus
pilotAttributeType 46 : : janetMailbox
```
```

--------------------------------

### MSM-ID and Board-ID Override

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/Documentation/dt-bindings.md

This allows overriding the autodetected msm-id and board-id for the downstream kernel. These values will be used by lk2nd instead of attempting to detect them.

```dts
	qcom,msm-id = <QCOM_ID_MSM8916 0>;
	qcom,board-id = <0xCE08FF01 1>;

```

--------------------------------

### International Organizations

Source: https://github.com/msm8916-mainline/lk2nd/blob/main/lib/openssl/crypto/objects/objects.txt

Lists international organizations and their associated identifiers, such as Secure Electronic Transactions.

```APIDOC
## International Organizations

### Description
Lists international organizations and their associated identifiers.

### Parameters
- **international-organizations** (integer) - Identifier for the organization.
- **id-set** (string) - Type of identifier set.

### Example
```
international-organizations 42 : id-set : Secure Electronic Transactions
```
```

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