> When I install NetBSD 4 Beta2 (200708030002z) from the i386 ISO (burned
> on a CD), it works fine.  Using the NetBSD 4 RC3 i386 ISO results in the
> system not being bootable.

How exactly does booting fail?

> During the installation process, I noticed that the final step when
> files are being copied (and the progress bar appears), with RC3 it slips
> by so quickly that it seems like it was missed; with Beta2 a few moments
> are needed to copy files to the hard drive.

So were the files copied to the hard drive or not? You could check for
example by running the installer again and mounting the filesystems
manually.

Was it a fresh install or an upgrade?