any reason I can’t choose usb in device selection? I tried on osx and win 10.
RPi, ATV or Vero?
atv
I’ve no idea, then, I don’t have one.
yea only sd is enabled, it won’t let me switch to usb, and I even have an SD, but it doesn’t show up on device selection. 
I suspect you can’t boot ATV from USB. You have to write the install image to SD, then that will write the system to a USB stick or HDD, depending on what you chose in the previous screen.
You don’t select USB or HDD because that option is chosen when you select the image.
i.e. 2017-04.1-USB or 2017.04.1-HDD
Then you write the image to a USB stick.
Install option doesn’t allow me to choose usb, and device selection shows up empty although I have a usb and an SD card. Does the removable media need to be a certain format? i know I should be able to use a usb, because ATV doesn’t have an SD Slot.
It does. Read again.
You leave it at SD and select USB anyway.
This has been covered a few times. See AppleTV Install can't select Install location for example.
ok sweet I’ll try a different usb maybe