Thanks, geneven, for your encouragement. Yes, I'll keep reflashing until I get things right.

After my third reflash things seem pretty stable. I can consistently mount the microsd as ext3 and I have emacs working pretty much the way I want.

When I turn the n900 off and then back on, I still hold my breath.

I've learned to be more careful in making backups to my microsd card and home computer. In particular, I do the following:

1. Use the built-in backup application to back up settings, applications, bookmarks, and communications/calendar.

2. Back up contacts from the contacts menu.

3. Back up other files in /home/user that I would have to replace. (.emacs, .profile, etc.)

4. Back up my downloads so reinstallation goes quicker.

On reflashing I first install rootsh, openssh, and midnight commander (to use as an editor). With these I can get the microsd mounted and transfer backups from the microsd and the home computer. After that it's just a few hours of putting things back the way I want them.