I need to build a custom kernel and kernel modules to based on the official Ubuntu image. And now, I have built the kernel Image and kernel modules.
Then I unpack the official image, and got the ramdisk directory from update.img (update.img–> ramdisk.partition --> ramdisk files) . Also, I have replace the kernel and module install into the ramdisk and repacked it.
But How can I just flash/update this part instead of the whole Ubuntu OS, for I have made some modifications to Ubuntu OS(the Rootfs partiton).
So How can I just update the ramdisk part? Thanks.