I think you mean backup and not firmware.
If you don't have you must rebuild it with Express or Webupdater and looking at missing files (like basemap for example) on forum.
Some files for sure can be copied from your faulty backup, but if you don't tell us what happened before you bricked it we cannot give advices.
Firmware can be found here:
Code:
Please Login or Register to see the links
NOTE: All these info can be easily found on forum. Try to read a bit