Comment 32 for bug 234185

As discussed on #ubuntu-installer:
17:29:46 < evand> hrm, cdrom-detect/ask-usb fails to account for the situation where you have a CD in the drive as well
*snip*
17:34:13 < evand> Right now I have an Ubuntu image on USB stick plugged in and a Windows drivers CD inserted into the computer.
17:34:44 < evand> It first mounts the CD, then goes into the try-usb block and mounts the usb disk over top of that.
17:35:38 < evand> If I stick a if [ "$mounted" = "1" ]; then break; fi before try-usb it goes with the Windows CD, which obviously fails.
17:36:29 < cjwatson> oh, hmm
17:36:33 < evand> I suspect in this scenario, it should try to mount, then check to make sure we're dealing with an Ubuntu image, if not go to the next device, if there are no devices left, fail
17:37:36 < cjwatson> I see what you mean, that's badly wrong