Ok, I your problem seems to be that your boot partition is >32GB. I *think* U-Boot has problems with large boot partitions.
Now start over from step 4 and create more partitions with fdisk. Make your first partition < 20 GB. Mine is 10GB

Then continue with other steps as instructed in the guide.
EDIT: You will probably need a swap partition ~1 Gig, and the rest can be used to store whatever you want. So create 3 partitions with the sizes I specified. When you boot up ArchLinux you will need to format the Storage partition and make use of swap (in the guides)