Did you try both of the Modded BIOS that I included ? One was done with SSV2 and one with SSV3 and they are labeled according to method used. Also I didn't Rename the SSV3 Modded BIOS to P20B200.BIN which is what it needs to be if you use the UpdateBIOS.bat included with the flash tools. You also might want to flash from DOS instead of Windows. You will need to get the proper flash tool from the manufacturers website to do that.
I've used both types, tryed with the standard version and the error still happens. The tools included are winflash.exe and updateBIOS.bat... I've tryed using both under dos/Windows, and none worked. I got the error using Afudos.exe and amiflash. On amiflash the error happened right after the question about boot blocker.
Can you link a screen from Slic Dump tool ? I might need to use a specific Toshiba SLIC for that to work.