Doesn't sound like a bricked device, just yet. Check the Wiki for info on how to flash, and make sure you do have a full battery before reflash.

http://wiki.maemo.org/Updating_the_firmware

If you have questions after reading that, please give some OS specific information of the device you are using to reflash.

You already stated that you didn't take the time to read the feedback from your terminal when applying apt-get upgrade. Perhaps it's best to forget about apt-get upgrade alltogether and use either FapMan of HAM to do updates.