Comment 5 for bug 820116

U-Boot is getting an error parsing the uenvcmd env setting. The current limit of number of tokens in a command line is 16, normally you can get around this by quoting things to put them in a single token but for some reason the import env doesn't grok that correctly so as an alternate work around you can split the command. Looks like you want to do a normal mmc boot if the pxe boot does not work so this should do the trick (works for me at least):

#pxecfg_ram=0x82000000
#ethaddr=00:02:03:04:05:06
#usbethaddr=00:02:03:04:05:06
autoload=no
bootargs=ro root=/dev/sda2 console=ttyO2,115200 debug earlyprintk elevator=deadline
#uenvcmd=usb start; bootp; pxe get; pxe boot; mmcinfo; fatload mmc 0:1 0x80000000 uimage; fatload mmc 0:1 0x81600000 uinitrd; bootm 0x80000000 0x81600000
mmcbootcmd=mmcinfo; fatload mmc 0:1 0x80000000 uimage; fatload mmc 0:1 0x81600000 uinitrd; bootm 0x80000000 0x81600000
uenvcmd=usb start; bootp; pxe get; pxe boot; run mmcbootcmd

The next release of u-boot-linaro will change the max args from 16 to 32 so this will be fixed but the work around is still a good idea because separating env commands into named subcommands serves to document what you are doing.