On my Marsboard I ran several times into the problem that when I started
yum update
after a reboot on finishing the update, my Marsboard wasn’t booting Fedora.
The problem was that the kernel packages were replaced with new ones, and the u-boot bootloader couldn’t cope with the situation. Probably the situation can be handled, but for now the safe way of updating the Fedora 19 on Marsboard A10 is
yum --exclude='kernel*' --exclude='uboot*' --exclude='arm-boot*' --exclude='dracut*' update
Why I do not advise to put the exclude directives in the yum.conf file? Because I tried it and the kernel became updated regardless of the exclude statements in the main section of the yum.conf file.
You can create a script named for example yumpudate.sh in your home directory, which you can use to save you the effort to write or copy/paste the whole command line.