Bios Mods -The Best BIOS Update and Modification Source

Hello,

Following I have expected / done facing POST code 97 after changin System S/N
 

1. I got  two SUN Ultra 40 M2 Workstrations
   
2. PhoenixBIOS 4.0 Release 6.1 
   
3. BIOS Version 1.24 (assume SUN versioning)
   
4. Updating the BIOS failed on one machine and the BIOS get corrupt and machine stuck in Power Cycle after plug-in the machine to power
   
5. unfortunatly I did not backup the BIOS before flashing (Stupid - I know).
   
6. Read the BIOS from the working machine using my USB Eprom/EEprom-Flasher
   
7. Modified in Hardware-Flash-Utility from USB Eprom/EEprom-Flasher the MAC adresses to the original value from failing machine
   
8. Written modified BIOS from working machine (previous step) with USB Flasher to EEPROM of failing machine
   
9. Failing machine succesfully power up and BIOS can be entered with F2
   
10. MAC adresses of failing machine correctly shown in BIOS screen - i.e. modification from step 7. works
    
11. OS (Scientific Linux) boots succesfully
    
12. Changed "System S/N" in the BIOS File from Step 8. to the value printed on the Label of the failed machine
    
13. Written modified BIOS to EEPROM to failing machine
    
14. Failing Machine power up but stops with POST Code "97" on Dual 7-Segment LED located on PCB - Machine beeps
    
    https://docs.oracle.com/cd/E19127-01/ult...8892_84069
    
    96 No Beep Code | Reset segment-register addressibility from 4GB to normal 64K by generating a Shutdown 8.
    97 No Beep Code | Create pointer to Multi Processor table in Extended BDA.
    98 Beep Code 1-2 | Search for option ROMs. Rom scan the area from C800h for a length of BCP_ROM_Scan_Size (or to E000h by default) on every 2K boundry, looking for add on cards that need initialization.
    
    
15. Assuming that Bios fails in POST Code 98 because machine beeps while POST 97 does not have Beep code  
    
16. Power down and repeat Steps 6,7,8
    
17. Changed "System S/N" in the BIOS File from Step 8. by only one Character and writing changes to EEPROM
    
18. Machine gives POST 97 again
    
19. Revert changes of System S/N to values of working machine but with changed MAC works again
    

Question:

1. Does PHLASH16 generate a checksum - and if yes, is it posible that the manual change of "System S/N" will result a wrong Checksum which brings machine to POsT 97/98 ?
   
   
2. PHLASH16 has parameter
   
   
   /C Clear CMOS checksum after programmingDoes this mean that BIOS verifies CMOS value of "System S/N" and if mismatch stop and this parameter deletes CMOS value ?Would it be sufficient to pull CMOS battery, wait an hour and retry or what does it mean ?
   
   
3. Since PHLASH16 has parameters
   
   /DSC:string Specify chassis serial number DMI string.
   /DSM:string Specify motherboard serial number DMI string.
   /DSS:string Specify system serial number DMI string.
   
   it would be interesting what parameter is required to get these values using
   
   dmidecode
   
   especielly to derive "System S/N"
   
   
4. Is there a chance that when using PHLASH16 with the saved BIOS (only MAC changed) but in combination with one of the parameters from 3. that checksum is calculated and machine pass BIOS and boot ?
   
   
   
5. If 4. is correct, what is the correct commad line for PHLASH when saved BIOS is named  "v124mod.bin" and  "System S/N" equals to ABCDEFG
   

thanks in advance
Frank