Add hardkernel-odroid-h4-plus placeholder docs

docs/unified/hardkernel/building-manual.md

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+# Dasharo firmware building guide
+
+## Intro
+
+This guide shows how to build Dasharo firmware for Hardkernel devices.
+
+## Requirements
+
+- Docker
+    + follow [Install Docker Engine on Ubuntu](https://docs.docker.com/engine/install/ubuntu/)
+    + follow [Post-installation steps for Linux](https://docs.docker.com/engine/install/linux-postinstall/)
+- Git
+    + `sudo apt-get install git`
+
+## Building
+
+To build Dasharo firmware image, first clone the coreboot repository:
+    ```bash
+    git clone https://github.com/Dasharo/coreboot.git
+    ```
+then follow the steps below:
+
+=== "Odroid H4+"
+
+    1. Checkout to the device's branch:
+            ```bash
+            cd coreboot
+            git checkout hardkernel_odroid_h4/release
+            ```
+
+    To build a specific version replace `hardkernel_odroid_h4/release` with
+    `hardkernel_odroid_h4_v0.9.x` where `x` is the version number.
+
+    2. Checkout submodules:
+
+    ```bash
+    git submodule update --init --checkout
+    ```
+    3. Build the firmware:
+
+    ```bash
+    ./build.sh odroid_h4
+    ```
+
+    The resulting coreboot image will be placed in the coreboot directory as
+    `hardkernel_odroid_h4.rom`.

docs/unified/hardkernel/firmware-update.md

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+# Firmware update
+
+The following documentation describes the process of Dasharo open-source
+firmware update. If your device is currently flashed with the proprietary
+firmware please refer to the [Initial deployment](initial-deployment.md)
+documentation.
+
+The update process may be different, depending on the currently installed
+Dasharo firmware version.
+
+For simplicity of the process we recommend using
+[Dasharo Tools Suite](../../dasharo-tools-suite/overview.md).
+
+Before starting the update procedure be sure to disable Dasharo BIOS Boot
+medium lock and Secure Boot:
+
+1. Power on the device.
+2. While the device is booting, hold the `DELETE` key to enter the UEFI Setup
+    Menu.
+3. Enter the `Dasharo System Features` menu using the arrow keys and Enter.
+4. Enter the [Dasharo Security Options](https://docs.dasharo.com/dasharo-menu-docs/dasharo-system-features/#dasharo-security-options)
+    submenu.
+5. Verify the state of the `Lock the BIOS boot medium` option - if the option
+    is chosen, press `Space` and then `F10` to save the changes.
+6. Go back to the main menu using the `ESC` key.
+7. Enter the `Device Manager` menu.
+8. Enter the [Secure Boot Configuration](https://docs.dasharo.com/dasharo-menu-docs/device-manager/#secure-boot-configuration)
+    submenu.
+9. Verify that the `Current Secure Boot State` field says Disabled - if not,
+    unselect the `Attempt Secure Boot` option below then press `F10` to save
+    the changes.
+10. Reboot the device to properly apply the changes.
+
+The settings of all the above options can be restored after a firmware
+update.
+
+=== "ODROID H4+"
+
+    ## Updating Dasharo
+
+    ```bash
+    flashrom -p internal -w hardkernel_odroid_h4_v<version>.rom --fmap -i bios
+    ```

docs/unified/hardkernel/initial-deployment.md

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+# Initial deployment
+
+Initial flashing of Dasharo firmware can be done from Linux using flashrom with
+the internal programmer. This document describes the process of building,
+installing and running flashrom on Ubuntu 24.04.
+
+## Build flashrom
+
+Please follow generic guide for [Dasharo flashrom fork](../../osf-trivia-list/deployment.md#how-to-install-dasharo-flashrom-fork).
+
+## Reading flash contents
+
+Always prepare a backup of the current firmware image. To read from the flash
+and save it to a file (`dump.rom`), execute the following command:
+
+```bash
+flashrom -p internal -r dump.rom
+```
+
+If you forgot to do this, you can get the original, proprietary
+firmware from the [ODROID wiki website](https://wiki.odroid.com/odroid-h4/hardware/h4_bios_update#bios_release)
+ to restore it in case it is bricked. Using the firmware other than
+your own backup should be the last resort.
+
+## Flashing Dasharo
+
+=== "ODROID H4+"
+
+    To flash Dasharo on the platform, execute the following command - replace `[path]`
+    with the path to the Dasharo image you want to flash, e.g. `hardkernel_odroid_h4_v0.9.0.rom`.
+
+    ```bash
+    sudo flashrom -p internal -w [path] --ifd -i bios
+    ```
+
+    After successful operation reboot the platform.

docs/unified/hardkernel/overview.md

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+# Overview
+
+=== "Hardkernel ODROID H4+"
+    - [Releases](../../variants/hardkernel_odroid_h4_plus/releases.md)
+    - [Hardware Configuration Matrix](../../variants/hardkernel_odroid_h4_plus/hardware-matrix.md)
+    - [Test Matrix](./test-matrix.md#hardkernel-odroid-h4-plus)

docs/unified/hardkernel/recovery.md

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+# Recovery
+
+## Intro
+
+The following documentation describes the process of recovering hardware from
+the brick state using an [RTE](../../transparent-validation/rte/introduction.md)
+and Dasharo open-source firmware.
+
+=== "V1000-series"
+
+    ## Prerequisites
+
+    * [Prepared RTE](../../transparent-validation/rte/v1.1.0/quick-start-guide.md)
+    * 6x female-female wire cables
+
+    ## Connections
+
+    To prepare the stand for flashing follow the steps described in
+    the [Generic test stand setup](../../unified-test-documentation/generic-testing-stand-setup.md#detailed-description-of-the-process)
+
+    ## Firmware flashing
+
+    To flash firmware follow the steps described below:
+
+    1. Login to RTE via `ssh` or `minicom`.
+    2. Turn on the platform by connecting the power supply.
+    3. Wait at least 5 seconds.
+    4. Turn off the platform by using the power button.
+    5. Wait at least 3 seconds.
+    6. Set the proper state of the SPI by using the following commands on RTE:
+
+        ```bash
+        # set SPI Vcc to 3.3V
+        echo 1 > /sys/class/gpio/gpio405/value
+        # SPI Vcc on
+        echo 1 > /sys/class/gpio/gpio406/value
+        # SPI lines ON
+        echo 1 > /sys/class/gpio/gpio404/value
+        ```
+
+    7. Wait at least 2 seconds.
+    8. Disconnect the power supply from the platform.
+    9. Wait at least 2 seconds.
+    10. Check if the flash chip is connected properly
+
+        ```bash
+        flashrom -p linux_spi:dev=/dev/spidev1.0,spispeed=16000
+        ```
+
+    11. Flash the platform by using the following command:
+
+        ```bash
+        flashrom -p linux_spi:dev=/dev/spidev1.0,spispeed=16000 -w [path_to_binary]
+        ```
+
+        > Flashing with flashrom takes about 1 minute.
+
+    12. Change back the state of the SPI by using the following commands:
+
+        ```bash
+        echo 0 > /sys/class/gpio/gpio404/value
+        echo 0 > /sys/class/gpio/gpio405/value
+        echo 0 > /sys/class/gpio/gpio406/value
+        ```
+
+    12. Turn on the platform by connecting the power supply.
+
+    The first boot of the platform after proceeding with the above procedure can
+    take much longer than normal.

docs/variants/hardkernel_odroid_h4_plus/releases.md

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+# Dasharo compatible with Hardkernel ODROID H4+
+
+Following Release Notes describe status of Open Source Firmware development for
+Hardkernel ODROID H4+
+
+For details about our release process please read
+[Dasharo Standard Release Process](../../dev-proc/standard-release-process.md).
+
+<center>
+
+[Subscribe to Hardkernel ODROID H4+ Dasharo Release Newsletter]
+[newsletter]{ .md-button .md-button--primary .center }
+
+</center>
+
+<!-- TODO -->
+[newsletter]: ./releases.md

mkdocs.yml

@@ -350,6 +350,14 @@ nav:
           - 'FAQ': variants/pc_engines/faq.md
           - 'Announcement': variants/pc_engines/post-eol-fw-announcement.md
           - 'Firmware write protection': variants/pc_engines/bios-lock.md
+      - 'Hardkernel':
+          - 'Overview': unified/hardkernel/overview.md
+          - 'Building manual': unified/hardkernel/building-manual.md
+          - 'Initial deployment': unified/hardkernel/initial-deployment.md
+          - 'Firmware update': unified/hardkernel/firmware-update.md
+          - 'Recovery': unified/hardkernel/recovery.md
+          - 'Hardkernel ODROID H4+':
+              - 'Releases': variants/hardkernel_odroid_h4_plus/releases.md
 # - 'Development Environment':
 #     - 'Nix': dev-env/nix-dev-env.md
   - 'Guides':