Have you tried the HDD in another console to see if it boots there?
Have you tried a different HDD with the faulty console? The fact that the 5035 flubbers at all makes me think either the EEPROM is fine, or it really doesn't care - You should be able to deal with the EEPROM via ConfigMagic if you can just get a dash to load...
If neither of those things shines any light on the matter, try
this. You build an EEPROM into a special BIOS that automatically programs your actual EEPROM chip accordingly. Since your HDD is unlocked, it doesn't *really* matter which EEPROM you use: Any Live banned one should do for the purpose of making the system boot again.