That post did not help. However, I decided to pull the battery and wait a really long time. The result is that it now fairly reliably leaves bootloader mode. One time it tried to refuse, but pulling the battery for only about three seconds let it boot.
For some reason it refuses to update via the new microsd card I just bought. (The bootloader shows for a bit, then a gray screen with a message appears for a fraction of a second, then the bootloader screen comes back. (Yes, the is under 2 GB, it is a 1 GB sandisk card).
I suppose my unit just has a personality defect.
