I'm relatively new to Linux and BT but I wanted to make a persistent USB install. I followed the video tutorial on the tutorial section of Offensive Security to the letter but it seems that trouble starts early.

After making the two partitions with fdisk I run mkfs.vfat[...] for the first partition (sdb1) and I get a message that sdb1 is a mounted volume. Furthermore when I mkfs.ext3[...] for the second partition (sdb2) I get a message that says the partition does not exist.

Originaly the USB was found as sdb and split in sdb1 and sdb2.

This is my first post so please show some mercy