I tried the method you said and I still cannot run the code "umount /media/mmc1". I got the same problems as before. I thought I might not need to run this code and went down. However, when I run "/dev/mmcblk0p1: 1,15000,6", it said that "/dev/mmcblk0p1 not found"

I spent almost a whole day on installing the system on mmc-mobile card but still failed. Please help! Thanks a lot!