cannot type into serial terminal

Hi all,
         After mistakenly erasing NAND flash , I cannot type anything
using keyboard into serial terminal. I have a working sd card which is
loaded with Angstrom , but at the beagleboard login prompt I cannot
type anything.Plz help.

sorry I was using screen in linux as terminal program, now I changed
to minicom and it is quite ok, but a lot of error messages.