[adamschuetze]

1) download an OS package, OTA
2) Reboot into recovery/update
3) use the bootloader to make a backup of your apps, or OS, or settings
4) Wipe and/or factory reset device
5) flash ROM with new OS package. Include checking to make sure this OS is designed for this particular hardware
6) reboot into new OS

As a bonus, no more desktop manager to maintain.

[howarmat]

you wont have access to pretty much all of the above mentioned anyway so it would be pointless to have a bootloader.

OS updates are handled within the OS as well as any backups you would be making