I'm trying to install Crouton on a USB Stick for Chrome OS.
sudo umount /dev/sda1
sudo mkfs.ext4 /dev/sda1
sudo mount /dev/sda1
mount: can't find /dev/sda1 in /etc/fstab
I dont know what Linux flavour you're using.
Mount appeared to fail and looked in the fstab file (/etc/fstab )for mounting options.
you could try.
~]# mkdir /mount/point ~]# mount -t ext4 /dev/device /mount/point
To mount permanently add to fstab. Ref /etc/fstab overview
All the best