title: uenvcmd in uEnv.txt can not be executed automatically
body: <p>I am using an arm board using TFTP and NFS but it got stuck at kernel loading as shown in the screenshot and I have to input the <code>run uenvcmd</code> then the process will keep going and everything is OK.
  <a href="https://i.stack.imgur.com/x1PNR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/x1PNR.png" alt="screenshot"></a></p>
  
  <p>Below is my uEnv.txt:</p>
  
  <pre><code># This uEnv.txt file can contain additional environment settings that you
  # want to set in U-Boot at boot time.  This can be simple variables such
  # as the serverip or custom variables.  The format of this file is:
  #    variable=value
  # NOTE: This file will be evaluated after the bootcmd is run and the
  #       bootcmd must be set to load this file if it exists (this is the
  #       default on all newer U-Boot images.  This also means that some
  #       variables such as bootdelay cannot be changed by this file since
  #       it is not evaluated until the bootcmd is run.
  autoload=no
  ipaddr=192.168.1.100
  serverip=192.168.1.13
  gatewayip=192.168.1.1
  staticip=${ipaddr}:${serverip}:${gatewayip}:255.255.255.0:::off
  bootpath=/tftpboot
  rootfspath=/opt/ti-processor-sdk-linux-rt-am57xx-evm-03.00.00.04/targetNFS
  
  #setting for kernel loading
  kernel_addr=0x82000000
  fdt_addr=0x88000000
  
  nfs_args=setenv bootargs console=ttyO0,115200n8 root=/dev/nfs rw nfsroot=${serverip}:${rootfspath} ip=${staticip}
  load_zimage=tftp ${kernel_addr} ${bootpath}/zImage
  loadfdt=tftp ${fdt_addr} ${bootpath}/am572x-idk.dtb
  boot_zimage=bootz ${kernel_addr} - ${fdt_addr}
  uenvcmd=run load_zimage; run loadfdt; run nfs_args; run boot_zimage
  </code></pre>
  
  <p>these is a strange file called <code>uboot.env</code> beside the <code>uEnv.txt</code>, too long to paste here, <a href="http://pastebin.com/WTV4hSEd" rel="nofollow noreferrer">uboot.env</a></p>