I've started the install-CD in rescue mode, opened a shell in a chroot, and did an "apt-get purge" to get rid of grub-pc in preparation of replacing it with the old grub package. Bit then, unlike the previous time, I checked and saw that /boot/grub was still full of files left there, including grub.cfg. So, I deleted the whole lot, before doing "apt-get install grub", "/usr/sbin/update-grub" and "/usr/sbin/grub-install". Now the reboot brought up the newly-installed Debian testing.
Some final thoughts: 1. The "apt-get purge grub-pc" command should not leave a whole directory full of config files that are subsequently used by grub-install. 2. Perhaps old and new grub should not share the same grub-install. 3. The Debian Installer should give users a choice when it wants to install a piece of crucial software that is still considered by many to be in beta (in this case new Grub vs. old Grub). Thank you for your consideration. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]