Openharmony的boot_linux.img 是标准的ext2格式，他需要通过syslinux来标准启动，但是鉴于有些uboot并没有默认打开syslinux，而使用默认的fit格式启动，所以本文介绍将原来的ext2的boot.img转换成fit格式的boot，从而使得系统加载更兼容

一、什么是fit镜像

关于fit镜像的说明，可以参考如下文档FIT镜像说明

二、its设置

为了打包fit格式的boot镜像，我们需要编写its文件，本文给一个示例文件如下：

/dts-v1/;
/ {
    description = "U-Boot FIT source file for arm";
 
    images {
        fdt {
            data = /incbin/("rk3568-evb1-ddr4-v10-linux.dtb");
            type = "flat_dt";
            arch = "arm64";
            compression = "none";
            load = <0xffffff00>;
 
            hash {
                algo = "sha256";
            };
        };
 
        kernel {
            data = /incbin/("Image");
            type = "kernel";
            arch = "arm64";
            os = "linux";
            compression = "none";
            entry = <0xffffff01>;
            load = <0xffffff01>;
 
            hash {
                algo = "sha256";
            };
        };
 
        ramdisk {
            data = /incbin/("ramdisk.img");
            type = "ramdisk";
            arch = "arm64";
            os = "linux";
            compression = "none";
            entry = <0x00000000>;
            load = <0x00000000>;
 
            hash {
                algo = "sha256";
            };
        };
 
        resource {
            data = /incbin/("resource.img");
            type = "multi";
            arch = "arm64";
            compression = "none";
 
            hash {
                algo = "sha256";
            };
        };
    };
 
    configurations {
        default = "conf";
 
        conf {
            rollback-index = <0x00>;
            fdt = "fdt";
            kernel = "kernel";
            multi = "resource";
            ramdisk = "ramdisk";
 
            signature {
                algo = "sha256,rsa2048";
                padding = "pss";
                key-name-hint = "dev";
                sign-images = "fdt", "kernel", "multi", "ramdisk";
            };
        };
    };
};

三、准备镜像

根据上述的its的描述，我们需要如下文件

# "rk3568-evb1-ddr4-v10-linux.dtb"
# "Image"
# "ramdisk.img"
# "resource.img"

3.1 dtb

对于openharmony，我们需要找到的dtb的位置在如下

out/kernel/OBJ/linux-5.10/arch/arm64/boot/dts/rockchip/xxxx.dtb

此时我们复制文件即可

cp out/kernel/OBJ/linux-5.10/arch/arm64/boot/dts/rockchip/xxxx.dtb fit/

3.2 Image

对于openharmony，我们需要找到的image的位置如下

out/kernel/OBJ/linux-5.10/arch/arm64/boot/Image

此时我们复制文件即可

cp out/kernel/OBJ/linux-5.10/arch/arm64/boot/Image fit/

3.3 ramdisk

对于openharmony，我们需要找到ramdisk的位置如下

out/rk3568/packages/phone/images/ramdisk.img

此时我们复制文件即可

cp out/rk3568/packages/phone/images/ramdisk.img fit/

3.4 resource

对于openharmony，我们需要找到resource的位置如下

out/kernel/OBJ/linux-5.10/resource.img

此时我们复制文件即可

cp out/kernel/OBJ/linux-5.10/resource.img fit/

四、制作boot

根据上述操作，我们可以开始通过mkimage制作镜像，先安装mkimage命令

apt install u-boot-tools

此时系统具备mkimage二进制，开始制作命令如下

mkimage -f boot.its -E -p 0x800 boot.img

制作时的日志信息如下：

FIT description: U-Boot FIT source file for arm
Created:         Fri May 24 03:34:16 2024
 Image 0 (fdt)
  Description:  unavailable
  Created:      Fri May 24 03:34:16 2024
  Type:         Flat Device Tree
  Compression:  uncompressed
  Data Size:    143744 Bytes = 140.38 KiB = 0.14 MiB
  Architecture: AArch64
  Load Address: 0xffffff00
  Hash algo:    sha256
  Hash value:   9df414ede45c3a2417bbcc4b8de9510aba9e2600f5a160a6a3b721c761400e31
 Image 1 (kernel)
  Description:  unavailable
  Created:      Fri May 24 03:34:16 2024
  Type:         Kernel Image
  Compression:  uncompressed
  Data Size:    24385552 Bytes = 23814.02 KiB = 23.26 MiB
  Architecture: AArch64
  OS:           Linux
  Load Address: 0xffffff01
  Entry Point:  0xffffff01
  Hash algo:    sha256
  Hash value:   4f3ad02eb1c101976b8b3dea5bce379efb0fd00a61a646b336c725d388dd4bea
 Image 2 (ramdisk)
  Description:  unavailable
  Created:      Fri May 24 03:34:16 2024
  Type:         RAMDisk Image
  Compression:  uncompressed
  Data Size:    2509910 Bytes = 2451.08 KiB = 2.39 MiB
  Architecture: AArch64
  OS:           Linux
  Load Address: 0x00000000
  Entry Point:  0x00000000
  Hash algo:    sha256
  Hash value:   027f5c7aa5ca3a2dde9d0bb744d3a508321308c1f47cb34b4053317e39fe6ecc
 Image 3 (resource)
  Description:  unavailable
  Created:      Fri May 24 03:34:16 2024
  Type:         Multi-File Image
  Compression:  uncompressed
  Data Size:    12588544 Bytes = 12293.50 KiB = 12.01 MiB
  Hash algo:    sha256
  Hash value:   bcd3ccc6ac2747de83f27d320bd3c3aed18762bb5f3045fa84ff926345e2a125
 Default Configuration: 'conf'
 Configuration 0 (conf)
  Description:  unavailable
  Kernel:       kernel
  Init Ramdisk: ramdisk
  FDT:          fdt

至此，我们可以获得boot.img用于fit启动