Change bootdelay value uboot

[ricar]

Hello,
I'm using A20 Olinuxino LIME with Debian GNU/Linux 7.6 (wheezy) image booted from NAND. I would like to change the value of bootdelay using U-boot shell. Setenv command works fine but when I send "saveenv" an error "Unknown command 'saveenv' - try 'help'" is displayed.
I compiled U-boot using A20-OLinuXino_Lime_defconfig.
How can I change the value of bootdelay?