====== VIM3/3L Secureboot ======

===== Introduction =====

The default image compiled by [[kg>fenix | Fenix ]] for ''Ubuntu/Debian'' does not support Secureboot. For ordinary users, Secureboot functionality is not necessary. 

Enabling Secureboot means that the board can only flash image signed with the same key, it won't be possible to flash any other unsigned image or image signed with a different key anymore. 

If you want to enable the Secureboot feature, you can follow this documentation to apply extra patches and sign the image.

<WRAP important >
  * Only support eMMC installation image.
</WRAP>


===== Warning =====

<WRAP alert >
Before you start, please note:
  * You know what you are doing and what you want to do.
  * Once the board is secured, we can't provide proper support for it anymore.
  * The Secureboot key can only be flashed once, and it is irreversible, so caution is advised when flashing.
  * The generated key must be securely stored because once the key is flashed, you will only be able to flash images signed with this key in the future.
  * Make sure to conduct thorough testing and ensure that the image is production-ready before enabling the Secureboot feature.
</WRAP>


===== Apply patches to support secureboot =====


Download and apply [[dl>development/patches/vim3-secureboot-patches.tgz | patches ]].

```shell
~/vim3-secureboot-patches$ tree
.
├── fenix
│   └── 0001-packages-images_upgrade-bump-to-1b40968.patch
└── u-boot
    └── 0001-don-t-decrypt-dtb-when-secureboot-enabled.patch

2 directories, 2 files
```

There 2 patches, one is for Fenix, and the other one is for u-boot.

===== Compile the image =====


You can compile the image after apply the patches.

===== Generate the signing key =====


Download the [[dl>products/vim3/tool/aml-signtool-g12a.zip | sign tool]] decompress it and double click ''AmlEToolV3.exe'' to open it:

{{:products:sbc:vim3:applications:secureboot-1.webp?600|}}

Select ''OneStepGenKey'' and check ''2048'' then click ''Generate'' to generate the keys:

{{:products:sbc:vim3:applications:secureboot-2.webp?600|}}


{{:products:sbc:vim3:applications:secureboot-3.webp?600|}}

The path of generated keys is in the ''key'' directory within the current sign tool's directory, named after the current time:

{{:products:sbc:vim3:applications:secureboot-4.webp?600|}}

You need to save the files ''aml-user-key.sig'' and ''SECURE_BOOT_SET'':

  * ''aml-user-key.sig'' - Used to sign the images
  * ''SECURE_BOOT_SET'' - Used to burn the key

===== Encrypt the image =====

<WRAP important >
  * Only support sign tool under Windows system.
</WRAP>

Also using the sign tool ''AmlEToolV3.exe'', select ''Entire'', import the ''User Key'', which is the file ''aml-user-key.sig'' generated before, 
and also check ''Only_BootLoader_Encrypt'' and ''Disable OTA sign''. Then import the image that needs to be encrypted in the ''Input'':


{{:products:sbc:vim3:applications:secureboot-5.webp?600|}}


{{:products:sbc:vim3:applications:secureboot-6.webp?600|}}


{{:products:sbc:vim3:applications:secureboot-7.webp?600|}}


Then click ''Encrypt'' to encrypt the image.

{{:products:sbc:vim3:applications:secureboot-8.webp?600|}}

{{:products:sbc:vim3:applications:secureboot-9.webp?600|}}



After successful signing, a new encrypted image will be generated in the original image directory, with a filename containing the ''secureboot'' suffix, 
e.g. if the orignal file is ''vim3-ubuntu-22.04-server-linux-4.9-fenix-1.5.2-230830-emmc-develop.img'', then the encrypted image is ''vim3-ubuntu-22.04-server-linux-4.9-fenix-1.5.2-230830-emmc-develop.20230830105011.secureboot.img''.


Next, we will explain how to flash this encrypted image.


===== Flash encrypted image  =====

<WRAP important >
  * Only support USB flash tool under Windows system.
</WRAP>

Download and install the [[dl>products/vim3/tool/usb_burning_tool_v2.2.0.zip | USB flash tool]], after installation, you need to copy the previously generated file 
''SECURE_BOOT_SET'' to the ''licence'' directory within the USB tool installation directory，e.g. ''C:\Program Files (x86)\Amlogic\USB_Burning_Tool\license''.

{{:products:sbc:vim3:applications:secureboot-10.webp?600|}}

Open the USB flashing tool, import the encrypted image, check the ''secure_boot_set'' option, and then click ''Start'' to start the flashing process.

{{:products:sbc:vim3:applications:secureboot-11.webp?600|}}


<WRAP important >
The key can only be flashed once, meaning you should only check ''secure_boot_set'' during the first encryption image flash.

Do not check it again for next time flashing with the same board.
</WRAP>

===== See Also  =====

You can find some documentations about how to flash the keys with Amlogic USB Flash Tool from the USB Flash Tool: ''About->Key Help'' and ''About->Burning Key Instruction'':

{{:products:sbc:vim3:applications:secureboot-12.webp?600|}}