I have an ext4 partition containing rootfs.
I need to implement a system update (uboot) which just extracts and writes the new rootfs image. This probably works like dd-ing the image into MMC flash to offset where the rootfs ext4 partition is said to be.
We are doing first MMC erase and then MMC write. The erasing operation is very slow (1-2 minutes). I am thinking that it may not be necessary and just writing new rootfs will do the trick.
The question is, suppose I am writing rootfs image that is smaller than the previous one: then there will be some residual data at the end right? Wouldn't this cause some problem when we for example run fsck?