Hang while moving switch to NAND

chetan
Hi all, 
I am new for friendly ARM. 
I am trying to boot by friendly arm board with android OS. 
For this I follow the step, which is maintained in
"http://sites.google.com/site/belina76/android-booting";; 
First time it works in NAND Flash. 
But from second time minicom is not responding(Hang) in NAND, but when I am
switching on my board with NOR, it working fine... 
Please help me out... 
I am stuck 
IS this problem is due to wrong process which is shown in above site??
Thanks in advance