How to Use a SPI Reverse Socket?

[오훈석]

                            

                                    Figure.1 SPI Reverse Socket & Direct writing adapter

1. Overview of SPI Reverse Socket & Direct writing adapter.
   A SPI Reverse Socket is a recovery tool to fix a suface mounted SPI SOP8 Flashrom without Reworks-tool.
   So, you can fix a suface mounted SPI SOP8 Flashrom without soldering with this tool.
   This tool has two usage according to circuit design of target mainboard.

   ※ Definitions:

    · Primary flashrom : A BIOS flashrom that soldered on motherboard

    · Secondary flashrom : A spare flashrom to boot with reverse socket

    · Flashrom Swap : Transferring a Primary flashrom interface to Secondary flashrom

2. The principle of Reverse Socket
   Question : Is it possible to update an on-board flashrom that is direct connected to my programmer?

    Answer :   No, it is impossible.

    As shown below, soldered flashrom is connected to many other unknown device in motherboard.
    So, if you tie programmer to flashrom without isolation of the flashrom, programmer will fail because of these unknown devices.

                    Figure.2 Simple connecting structure of BIOS Flashrom and Motherboard

        Figure.3 concept - When flashrom was connected directly to programmer without disconnecting from the

                                     motherboard, unintended connection is created.

    At worst case, if power is overloaded, motherboad, power unit, programmer, flashrom and on board the various
    components (CPU, memory, VGA, Harddisk...) can be fried.
    So, you should NEVER EVER try this.
    We need a new method, and one of simple method is adding a secondary flashrom.
 

                         Figure.4 Cconcept -  Adding of new flashrom, red-line is reverse socket.

    In this case, we have to make the Primary flashrom disable when attaching the Secondary flashrom.
    So, reverse socket must have a function that is a disableing a Primary flashrom.
    Result, motherboard can boot to OS with Secondary flashrom.
    After boot, you can pull-out a 'Reverse socket and Secondary flashrom' from M/B,

    and it will re-enable a Primary flashrom without POWER OFF.
    In this status, we can update(or fix) Primary flashrom with BIOS update tool of motherboard manufacture.
    (BIOS update tool : AWDFLASH, WINFLASH, PHLASH,AMIFAUTO, FLASH85x, AFUDOS, AFUWIN, UNIFLASH...)
    As a result, you have a chance to update a BIOS without soldering by Reverse socket.
    And you should understand reverse socket has two functions.
     · to disable/ebable Primary flashrom and Secondary flashrom.
     · to make a connection between Primary flashrom and Secondary flashrom without soldering.

3. Function description of SPI Reverse Socket & Direct writing adapter

                                           Figure.5 : Layout

    3.1. SPI Reverse Socket Board
      This board has function of Reverse socket(see above) for 8pin SMD SPI flashrom of PC mainboard.
      It makes a physical link between a Primary flashrom and Secondary flashrom(by Test Clip without soldering).
      And it disable a Primary flashrom and bypass BUS to Secondary flashrom.
      Result, motherboard can boot to OS with Secondary flashrom.

      ※ Caution
       a. Secondary flashrom is writed with correct BIOS file of target M/B before use. 
           So, you should  have a SPI progammer.
       b. As above, Secondary flashrom must be compatible or same with Primary flashrom.
       c. SPI Reverse Socket can work only with standard SPI circuit design of INTEL.

           Most of M/B follows a Intel design rule.

           However, some manufacturers has their own design.

           In this case, SPI Reverse Socket may not work.
           Please test a design check point of your M/B before purchase.

    3.2.Direct writing adapter
       This board makes a physical link between your 8pin SMD SPI flashrom

        and Programmer's DIP-8pin socket(by Test Clip without soldering).
       A flashrom of some M/B or most of 24C** EEPROM(needs a 24C programmer) can be writed with this adapter.
       Howevr, it is dependent on circuit design of tager M/B.
       Please read above 'The principle of Reverse Socket'.

       I don't guarantee about your wrong application.

4. Useage of SPI Reverse Socket & Direct writing adapter. 

    4.1. Useage of SPI Reverse Socket

            Parts needed :  SPI Reverse Socket board, Test Clip, Secondary flashrom(compatible with Primary Flashrom) 

            Conditions to Use : 
             a. Only for SPI flashrom on PC M/B. (don't use with other interface like 24C, 93C)

             b. In standard design, there is a resistor between Vcc and #HOLD pin like next picture.
                 The resistor must be over 600 ohm.
                 If Vcc and #HOLD is tied directly or resistor is under 600 ohm, SPI Reverse Socket board can not work.
                 Check it with multimeter before use.
          

                                                         Figure.6 Design rule check
       
            USEAGE :

             a. Write a correct BIOS of target M/B to Secondary flashrom with your Programmer.
                * Secondary flashrom must be compatible or same with Primary flashrom.
                  (Most of case, SST25VF016 is compatible with under 2Mbyte SPI flashrom)

             b. Insert the Secondary flashrom to J3 socket of SPI Reverse socket adapter.

             c. Combine a TEST CLIP ot J4 of SPI Reverse socket adapter.
                  (Yellow wire is Pin.1, Check with Layout photo.)

             d. Nip a Primary flashrom with TETS CLIP.

                 * Caution :
                   a. Target M/B must be in Power OFF status.
                   b. Yellow wire is Pin.1, Check with Layout photo.
                   c. Flashrom and it's PCB has a marking(dot, latch or tab) at Pin.1 side.                      
                   d. Isolate SPI Reverse Socket board from M/B.
                  

                                                        Figure. 7  Nip a TEST CLIP to SMD 8pin ROM.

             e. Turn on target PC. M/B will boot with Secondary flashrom.
                  (recommended to copy a BIOS update tool and BIOS file to harddisk before boot)

             f. When, OS is fully booted and ready to run the BIOS update utility,
                 Remove the TEST CLIP from Primary flashrom carefully.

             g. Update a Primary flashrom with manufacturer's BIOS update tool.

             h. If success, reboot the motherboard and check there is not problem.

    4.2. USEAGE of Direct writing adapter

          Parts needed :  Direct writing adapter, Test Clip, A Programmer

            Conditions to Use : 

                    a. Need to understand 'How it works'. 
                        Direct writing adapter can't wotk with most of flashrom in PC M/B.

                    b. Programmer's 8pin pin-out will be tied to flashrom's each pin with 1:1 pinout.

            USEAGE : 
             a. Combine a TEST CLIP ot J2 of SPI Reverse socket adapter.
                 (Yellow wire is Pin.1, Check with Layout photo.)

             b. Nip a Primary flashrom with TETS CLIP.

                 * Caution :
                   a. Target M/B must be in Power OFF status.
                   b. Yellow wire is Pin.1, Check with Layout photo.
                   c. Flashrom and it's PCB has a marking(dot, latch or tab) at Pin.1 side.                      
                   d. Isolate Direct writing adapter board from M/B.

             c. Connect J1 of Direct writing adapter to your programmer's correct socket.

            

                                                                                 Figure.8 Example

          d. READ or WRITE flashrom with Programmer's S/W.
              Recommend : If there is a ID funtion, Check it first.

                                   If there is error, you can't use Direct writing adapter.