The error message because mmcblk1p1 is NOT there, so either umount the whole sd card or just simply ignore the error message. xterm sudo gainroot umount /media/mmc1 or just ignore the umount command, continue with your partitioning. when done, reboot, xterm cat /proc/partitions should show a mmcblk1p2 (ext3), if it is there, you are alright and proceed with installation umount error message means a lot of things, most of time, just proceed will be fine. If they are serious, they will warm you the 2nd time, then you would have to think. 1st time umount error message are bogus mostly. Of course this is just a rule of thumb, dont take it as a bible bun