Ubuntu u-boot does not have run update defined command

Android uboot does not even have ext4load command:

Hit Enter or space or Ctrl+C key to stop autoboot -- :  0
Unknown command 'ext4load' - try 'help'
Unknown command 'ext4load' - try 'help'
kvim#

and thus I cannot boot ArchLinuxArm from micro SD card. @Gouwa please work on this, I can understand that currently two u-boot are needed because of that cache partition for Android, but at least they should be both on same level from feature.
In that HowTo for ArchLinuxArm i need to write that they must use Linux u-boot (one which comes with Ubuntu) as I don’t create FAT partition.