My starting point is Fedora 19 booting ok on my MK802II ( so working u-boot).
Because I have not found a way to access the u-boot prompt on the MK802II the steps I have used are:

make -j5 ARCH=arm CROSS_COMPILE=/usr/bin/arm-linux-gnueabihf- menuconfig
make -j5 ARCH=arm CROSS_COMPILE=/usr/bin/arm-linux-gnueabihf- LOADADDR=0x40008000 uImage dtbs
make ARCH=arm CROSS_COMPILE=/usr/bin/arm-linux-gnueabihf- -j5 INSTALL_MOD_PATH=output modules
make ARCH=arm CROSS_COMPILE=/usr/bin/arm-linux-gnueabihf- -j5 INSTALL_MOD_PATH=output modules_install

put a copy of the created uImage and arch/arm/boot/sun4i-a10-a1000.dtb into the boot partition of the sdcard
copy the created modules to the /lib/modules on the rootfs partition

In case the existing boot.scr has some incocnsistency I save this to boot.cmd:
setenv bootargs console=ttyS0,115200 root=/dev/sda1 rootwait ro earlyprintk debug
ext2load mmc 0 0x46000000 uImage
ext2load mmc 0 0x49000000 sun4i-a10-a1000.dtb
env set fdt_high ffffffff
bootm 0x46000000 - 0x49000000

and run:
mkimage -C none -A arm -T script -d boot.cmd boot.scr

copy this boot.scr to the boot partition of the sdcard

But alas it fails to boot so I am missing something somewhere.

Also tried this alternative method:

cat arch/arm/boot/zImage arch/arm/boot/dts/sun4i-a10-a1000.dtb > zImage_w_dtb
mkimage -A arm -O linux -C none -T kernel -a 40008000 -e 40008000 -d zImage_w_dtb uImage

but maybe should be .....     -a 0x00008000 -e 0x00008000
Any thoughts?