Just in case someone has the same issue I had, I'm posting the process of removing the Phoenix BIOS hard-coded password on the FUBA 3104ML (LY20C390) 1Ghz VIA industrial single board computer (SBC).

After much trouble with this, I decided to go hands-on. The routine advice of clearing the CMOS, removing the battery, and trying universal Phoenix passwords all fail to bypass the admin hard-coded password for this SBC. In researching, the issue appeared to be a security EEPROM that stores the password hash.

Hands-on approach!

At this point, I didn't care about cracking the password and I don't have the knowledge to do so anyway. Long story short, removing the EEPROM will immediately restore access to the BIOS. In this state, the BIOS error of "Unable to write to EEPROM" persists. Even with this error, the SBC seems to function correctly including keeping time and changes to the BIOS settings. I backed up this EEPROM and wiped it. After reinstalling the erased EEPROM, the BIOS errors and the security password prompt are gone! I need to take the next step and re-dump to see if the BIOS formatted things and potentially see where the hash was located (EEPROM data is only 512 bytes). At this point, I don't really care since the unit is fully functional. I'll include my dump in case anyone is interested in examining it.

The IC in question was on the back of the PCB and is marked (24C04AN) which is a 4K 5.0V I2C Serial EEPROM. You will need to remove the EEPROM since the 5V lead is connected to the rest of the system and will complicate things if trying to program while installed. I used my TL866CS programmer to read and wipe the EEPROM, but any 5V-compatible reader should work. Unless you're good at soldering wires to the IC, you'll need a SOIC-8 breakout PCB to hold the chip for programming. As mentioned, the SBC will work with this chip removed however, there will be a persistent error on reboots. To solve this simply erase the EEPROM and reinstall. Good luck and I hope this info helps others encountering older Phoenix BIOS hard-coded passwords.

EEPROM DUMP