How to make a kernel image for AI7688H module ,How to add a custom firmware image as a part of kernel image

1.How can i add a custom firmware image as a part of kernel image (If i run "sysupgrade -v kernel.bin" then my custom image should be loaded in to root)?
2.While following documentations of ACSIP i have tried build steps and after executing "make -j1 V=s" it runs for almost 2 hour and exited with below mentioned error message how to resolve this.

<linux_kernel/AI7688H_OpenWRT_Build_FW_Setting_Tool_V1.0/openwrt/dl/ && rm -rf mjpg-streamer-r182;
Checking out files from the svn repository...
svn: E230001: Unable to connect to a repository at URL 'https://svn.code.sf.net/p/mjpg-streamer/code/mjpg-streamer-experimental'
svn: E230001: Server SSL certificate verification failed: certificate has expired
svn: E230001: Unable to connect to a repository at URL >

you're asking us why some random site on internet isn't working properly ?

can you give an answer for first one?

I don't understand your first question. OpenWrt firmware images always contain kernel and rootfs and are flashed using sysupgrade.
What are you trying to achieve here?

The modern buildroot allows you to include custom files into your image. Since you're using some vendor fork, however, you'll need to check with them what they support. Usually they build on outdated OpenWrt releases (15.05, 14.07, ...).

How can I integrate the 'system_fw.tar' file into the "rootfs" so that it becomes an integral part of the system, ensuring that upon powering up the device, the file is automatically available in the "root" directory?

'system_fw.tar' file this is a custom tar file...

add it as a package, with your custom content as payload ?

Could you please recommend a resource or provide a link to documentation that guides through the process described, especially regarding integrating files into the root filesystem and building custom firmware in OpenWrt?

What you're looking for probably: