I want to explicitly set rootfs size to 4GB for update compatibility reasons. If I set IMAGE_OVERHEAD_FACTOR = "1", IMAGE_ROOTFS_SIZE = "4194304" and IMAGE_ROOTFS_EXTRA_SPACE = "0", rootfs partition has 5.1 GB. If I print these variables on do_rfs_postprocess step, IMAGE_ROOTFS_EXTRA_SPACE has value 0 + 102400. But I don’t know, where the additional gigabyte came from.
How can I set rootfs part size exactly to 4 GB, no matter what?