extlinux: cannot open device /dev/sdb1
 

when I install the extlinux to a CF card by typeing:
extlinux -i /mnt
which the /mnt is the mounted CF card.
then, folow message occured.
extlinux: cannot open device /dev/sdb1
So. How to solve this problem?

Are you sure the /mnt is really /dev/sdb1? Also, please check if the filesystem on the card can be read by Linux. Normally it is the case. Just an ls in the directory should be enoug to find out.