Comment 8 for bug 1567445

I'd also like to know how "now or never" this actually is. I've been trying to find documentation about this feature but haven't succeeded so far.

@matthew-wilson: once I had the error I'd always get it on retry no matter what options I chose. On reboot (or maybe just restarting ubiquity, can't remember) if I didn't choose disable secure boot then I didn't get an error.