[FreakinSyco]

I think you have to have USB plugged in in order to be able to see ESC device selection on the sea bios screen. If there is only one bootable device it will just boot that.
There is either 1 sec or 30 secs boot delay on your Chromebox.
If there is 30 secs then you should have no issue as soon as you see developer mode warning you can hit ctrl+l and then immediatelly press ESC key.
If there is 1 sec delay then you need to practice a bit if your display and keyboard are not initialized right at startup. That 1 sec starts almost as soon as you hit the power button when the device is off.
If you would like to boot from connected USB or inserted memory card you should finally hit number two in the upper row of keys. However you will see clear instructions when to press this.

I've got the standalone bios setup, so no ctrl+l. Yes I think it boots in one second. I did get everything sorted. I switched to a new USB drive. I still could not get my celeron based unit (that I corrupted openelec on) to ever get to the boot screen, but I could finally get my i3 based one to boot to the boot menu. So I did the sensible thing... open both boxes swap out the SSDs, install Mythbuntu on the i3, swap the SSD back into the Celeron based one. Then put them back together and redid openelec on the i3. What fun.

On another note: I went back to the standard OpenELEC 6.0 away from the EGL new build that does better colors. I had issues with audio passthru being flaky. GUI sounds would not play consistently and the image seemed softer IMO. Now back on main OpenELEC everything is nice and smooth. I cant tell the difference in any colors. And it annoyed me that auto updates were disabled when using the EGL build.

Big thanks to everyone who developed everything that got linux booting on these boxes. These are by far my new favorite devices.