Upgrading Angstrom on Beaglebone without reimaging?


Now that a new Beaglebone Angstrom image is available at
http://www.angstrom-distribution.org/demo/beaglebone/, I think a lot
of new BB users are wondering if they can upgrade without having to
reimage the SD card and re-do their customizations.

I took a shot at upgrading U-Boot and the kernel as follows (using a
Windows PC):

- Use 7-Zip to open the img.gz file, then 7-Zip again to open the .img
- Extract the 0.fat folder. This is the FAT32 partition with the U-
Boot and kernel files.
- Connect the BB's microSD card into Windows - it will assign a drive
letter to the FAT32 partition
- Copy the files from 0.fat to the BB microSD card

This works, but I don't know whether it is a good idea. A couple of
questions, if anyone knows the answer:

1. Does running "opkg update" and "opkg upgrade" also update U-Boot
and/or the kernel on the FAT32 partition?

2. If I started with the 2011.11.16 Angstrom demo image, did the above
to update U-Boot and the kernel, then used opkg to upgrade everything
else, what would I be missing from the 2011.12.26 image?