# Boot

The boot device tree properties provide information on how to enable and
disable user-initiated emergency download (EDL) in XBL. The boot DT
properties also describe the EDL timeout and the USB cable options that
can force the system into the EDL mode. The boot DT properties are used
to configure the boot-related functionality.

The boot DT file path on the Linux build machine is `/boot_images/boot/Settings/Soc/<chipset>/Core/Boot/sw_boot.dtsi.`

| Property name | Property description | Data type | Possible values/value range | Device behavior |
| --- | --- | --- | --- | --- |
| `vibration` | Turn on/off vibration at XBL exit. | UINT32 | <ul class="simple"><br><li><p>0x00</p></li><br><li><p>0x01</p></li><br></ul> | <ul class="simple"><br><li><p>ENABLE (0x01): Turns on the vibration. 0x01 is the default setting.</p></li><br><li><p>DISABLE (0x00): Turns off the vibration.</p></li><br></ul> |
| <br>`forced_download.feature` | <ul class="simple"><br><li><p>Enable or disable the force emergency Download mode (EDL) feature at the XBL stage.</p></li><br><li><p>To flash images using USB cable along with key combination (POWER (PWR), VOL+ and VOL-keys pressed together)</p></li><br></ul> | <br>UINT32 | 0x00 | Force EDL feature (FEDL): DISABLE (0x00): FEDL is disabled. |
| <br>`forced_download.feature` | <ul class="simple"><br><li><p>Enable or disable the force emergency Download mode (EDL) feature at the XBL stage.</p></li><br><li><p>To flash images using USB cable along with key combination (POWER (PWR), VOL+ and VOL-keys pressed together)</p></li><br></ul> | <br>UINT32 | 0x01 | ENABLE (0x01): Enable user-initiated EDL in XBL. |
| <br>`forced_download.check_usb_option` | <br>To enter FEDL mode, select USB cable options | <br>UINT32 | 0x00 | FEDL feature configuration:<br><br><br>CHECK\_USB\_D\_PLUS\_GROUND (0x00): The device is forced to EDL when it is powered on with a special USB cable where the D+ line is grounded. Default settings |
| <br>`forced_download.check_usb_option` | <br>To enter FEDL mode, select USB cable options | <br>UINT32 | 0x01 | CHECK\_USB\_D\_PLUS\_HIGH\_WITH\_TIMEOUT (0x01): Connect the device to USB+ grounded during boot and within the boot timeout, which when removed forces the device into EDL mode. |
| <br>`forced_download.check_usb_option` | <br>To enter FEDL mode, select USB cable options | <br>UINT32 | 0x02 | <ul class="simple"><br><li><p>Time out is provided by the <code class="docutils literal notranslate"><span class="pre">forced_download.check_dp_timeout</span></code> DT property in milliseconds (ms)</p></li><br><li><p>CHECK_USB_REGULAR_CABLE (0x02): The device is forced to EDL when booting with a normal USB cable.</p></li><br></ul> |
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## UEFI

> 
> 
> In the UEFI environment, the nodes are part of the device path protocol, which defines how devices are connected and identified.
> The UEFI file path on the Linux build machine is `/boot_ images/boot/Settings/Soc/Core/Uefi/cfg/ueficfg.dtsi.`
> The main types of UEFI device path nodes and property names are:

| DT property name | Data type | Possible values/value range | Description |
| --- | --- | --- | --- |
| OsConfigTableSelection | UINT32 | Range is from 0x1 to 0x2 depending on the Hypervisor. | - Provides information on which Hypervisor to be used. The values are as below:<br>    - <ul class="simple"><br><li><p>0x1 - BOOT_TYPE_LINUX - GUNYAH</p></li><br><li><p>0x2 - BOOT_TYPE_LINUX_WITH_KVM</p></li><br></ul> |
| QcCapsuleRootCert | UINT8 list | Has the OpenSSL generated certificate content. | - Root certificate for capsule authentication. This node has<br>    - the entire root certificate content, which is used to<br>authenticate the capsule. This node is also used for<br>firmware updates. |

Last Published: Dec 30, 2024

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