[tadad1]

elkid,
In most cases yes if you load a firmware that is not compatible with your player you can generally fix it by reloading your backup dump.
In some cases it can be a problem, when you do a backup dump there are 10-12 files within your players firmware that are not backed up and as yet no one has come up with a way to extract the full firmware from your player. Problems can occur if the firmware you are updating to is incompatible and over writes any of those files that are not included in your backup dump. If this happens your backup may not restore your player or your player may no longer be recognised by the upgrade software and you can not flash your player. When this happens you have to short your memory chip to reset it and then find a full version firmware that will work with your dump to restore your player.

My experience has been that a backup will work about 95% of the time but occassionally I find a firmware that kills my player completely.