[Solved] Where's my rootfs?

Please try following:

  1. set bootargs as
    bootargs="ubi.mtd=rootfs root=/dev/ubiblock0_2"

Please also try following:

  1. rename mtd partition name "rootfs" to "ubi"
  2. drop bootargs line

I have tried adding support for the device of ipq806x, but I have no experience with the device of ipq40xx. So, I am not very confident about the second procedure...