After running a mediacheck with anaconda-11.4.1.6, loader is unable to find the
disc under any circumstances.

There's two bugs at work here. First, the kernel doesn't tell us properly when
the drive is checking media. This causes the mount command to fail with 'No
medium found'. There's another bug (somewhere) about this, but the workaround is
to wait a few seconds after inserting the disc before hitting "OK".

*This* bug is that, even if you wait ~20 seconds after inserting the disc,
loader can't find it and ejects it again. 

The logs show no errors returned from the mount command, and the kernel emits
iso9660-specific filesystem probing messages. So I believe it *is* being mounted
properly.

I think the problem is that loader2/cdinstall.c has the logic inverted on this
access() call:

                if (!access(stage2loc, R_OK)) {
                    free(stage2loc);
                    umount(location);
                    ejectCdrom(dev);
                    wrongCDMessage();
                    continue;
                }

access(2) says "On success (all requested permissions granted), zero is
returned." So the test should probably be: 

                if (access(stage2loc, R_OK) != 0) {