For the jailbreak of Apple TV 1st generation you will need to create an SSH install patchstick, run the ATV USB Creator software and an USB Stick formatted to a single Mac OS Extended (Journaled) partition with a GUID Partition Table.
Step 2: Connect the USB Stick to your Mac and launch the atvusb-creator app in the extracted folder on your desktop.
Step 3: The wizard will ask you to download the app from the Internet. Click Open to launch the installation process.
Step 4: In the first display window select “ATV-Patchstick” under the Choose an Installation dropdown menu. In the right part of the window, under the Installation Options, select “ssh tools” from the dropdown menu.
Step 5: Check to make sure the wizard has selected the right USB stick. Press Create Using and check for the USB.
Step 6: Now the wizard will begin the download process of the AppleTV Update DMG. Wait patiently until the jailbreak program informs the patchstick was installed successfully.
Step 7: The USB Stick you were using during the jailbreak installation has been renamed and is now called PATCHSTICK. You will also notice the USB now contains the jailbreak files. Now Eject the stick and connect it to your Apple TV 1st generation.
Step 8: You will have to reboot the device, holding down the Menu and – buttons on your remote. Wait patiently for the Patchstick on your USB to complete the SSH installation on your device. When that’s done with, remove the USB stick, then unplug and plug your Apple TV to reboot.
Step 9: Enjoy.