Update: Easy way to get Apple TV boot.efi

Apparently, the file lives in the "firmware" DMGs that Apple offers for download. The most recent version at the time of writing is available from Apple here. You might find a more recent version listed at the bottom of the page on the AwkwardTV wiki, which also features a great collection of information about hacking with Linux on your Apple TV.

To get a copy of boot.efi (on a Mac)

Download the file, and mount it by double clicking; it should mount as /Volumes/OSBoot. On this mounted filesystem, navigate to System/Library/ and copy the boot.efi file you find here. That's all!

The previous post is still valid as a means of ssh-ing into you Apple TV, fun for tinkering anyway :-)

Enable ssh on Apple TV

It has been a long time , but I am going to try and post more frequently again. Lots of technologically cool things have happened since I last posted. Most recently, I helped a friend install OS X onto an external USB drive in a way that makes the USB drive bootable on an Apple TV!

I followed the directions here mostly:
http://www.hackint0sh.org/forum/f98/634.htm
There is a section where it mentions a boot.efi file, but no link or hint or info is given. So, this is how you get the boot.efi file.

Update: I posted a much easier way; This guide remains valid as a way to enable ssh.

The approach is to install an ssh daemon onto the Apple TV, and then copy the boot.efi file to your local machine. On a Mac:

1. Get the atvusb-creator, and run it
2. Make a USB stick or drive with that tool. For this, we only need the ssh daemon, so untick the other options:
   
3. In the "Create Using->" drop down, choose your USB device which will be the vector for the ssh change.
4. Click the "Create Using->" button. atvusb-creator will download the Apple TV firmware. Let it do its thing.
5. When its done, eject the USB drive and plug it into a powered-down Apple TV, and then power up. You'll be greeted by Tux sitting on an Apple TV, followed by a kernel boot and some messages! It will install the patch, and then prompt you to yank the power on the Apple TV. Remove the flash when you do so, then power up the Apple TV.
6. Navigate the Apple TV setup menu until you find the Network settings which specify the IP address of the Apple TV. Lets call this a.b.c.d
7. From your Mac now, open a terminal.
8. scpssh frontrow@a.b.c.d:/System/CoreServices/boot.efi .
9. The password is frontrow

Congrats, you now have made a copy of the boot.efi from your Apple TV! Now use that file in your procedure as specified in the link above. are in to your Apple TV! Play around with the terminal and enjoy!