Making a small image using BusyBox

[MichaelBMiner]

I have created an image using bitbake imx-image-core. My wic.bz file for my SD card is 167.6MB. I want to make my kernel and image as a whole as small as possible. To do this I am trying to use busybox.

In my local.conf I added the line

VIRTUAL-RUNTIME_dev_manager = "busybox-mdev" as per the yocto mega manual.

I performed the commands

bitbake -c menuconfig busybox

bitbake busybox

bitbake imx-image-core

I am told this was successful but my wic.bz image has remained the same size.

Are there any other steps to getting busybox active on the device, and is there a way to view kernel build size?

[b36401]

Please check if much space is reserved with IMAGE_ROOTFS_EXTRA_SPACE option.

[MichaelBMiner]

Where is this option? 

[josephzhou1]

Alternatively, you can ensure a specific amount of free disk space is added to the image by using the IMAGE_ROOTFS_EXTRA_SPACE variable.

put it to zero