Kernel 4.9.44 ignores rootfstype=ext4 and tries only squashfs,jffs2 for rootfs

Hi @all,

My board has an 8GB eMMC Flash storage. One partition is formatted with ext4 and contains the lede rootfs.

I boot the kernel with the parameters root=/dev/mmcblk0p2 rootfstype=ext4 and got a panic when rootfs should be mounted.

    No filesystem could mount root, tried: squashfs jffs2

I have set CONFIG_EXT4_FS=y, and has disabled squashfs, ubifs and so on via menuconfig.
The kernel only tries squashfs and jffs2 but ext4 is fully ignored.

Any idea what is ging wrong here?

PS:
Extroot, overlay, pivot_overlay ... are no options.