The PS3's Firmware remains untouched, so technically it's not a brick but rather a bug. I have heard that people have seen the download jump from 50% to 100% right away. Between those those percentages are integrity checks and for some reason they were skipped. After the PS3 will boot and attempt to load that update file but it will be unable to as it's not complete.
Fix 1: Replace the Hard Drive so the ps3 will boot the last firmware you were on. (Firmware was never updated) Then the PS3 will ask you to format it so do so.
Fix 2: (You will lose all game saves) If you don't have two hard drives you could always hook the hard drive up to your computer and reformat it. Then put back into your PS3 and the PS3 will ask you to format it.