No working init found.

[live-2-code]

Hi, I am using a custom ext4 rootfs (it's working rootfs) with the debian-build instruction, which follow the step to create the dtb file, Image and l-loader, and transfer file with TFTP.

However, i am getting the error [ 2.911915] ---[ end Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/init.txt for guidance.

In this case, how can I modify the rootfstype and maybe the root= parameter?
Or else there is other issue causing the init not found?
Thank you.