How to Unlock MB SD Connect C4 by PCB Modification

One of my friend told me like this : ” If you have a MB SD Connect C4 and its Locked,you do not need buy a new one ,just change this chip , all will be okay  ” He also side ” You can try with it but also has risk ”

Here is his experience shared with us :

PCB modification procedure:

1- Carefully open the sd connect multiplexer

2- Check whether some part is easy broken

MB SD Connect C4 printed circuit board in a good condition should be:



sd-c4-pcb-solve-lock-4  sd-c4-pcb-solve-lock-2 sd-c4-pcb-solve-lock-3

3- Possible occasion:

Maybe batteries leaked and damaged the PCB.
4- Blow the chip marked with a red circle by a electric hair drier


5-Disassemble the chip

6- Write the program to a new chip

7- Install the new chip to the PCB, then assemble PCBs into SD connect c4 mux

8- Start SD c4 mux

9- Connect MB SD C4 multiplexer to the laptop

10- SOLVED! And work like a charm, as a good SD Connect C4 at

Done ! That’s all my friend shared with us.

Hope it would help you.

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