Creating a bootable USB stick (or other media, like DVD) is easy in SCCM 2012. To create a bootable USB stick or DVD in SCCM 2012:
- In the SCCM 2012 console, select the Task Sequence for the image you want to make bootable media for (Software Library -> Overview -> Operating Systems -> Task Sequences)
- Click on Create Task Sequence Media
From here, follow the wizard to create a bootable USB stick (or other media such as CD or DVD) for the SCCM 2012 deployment.