This guide will walk you through changing the serial number of your MacBook using a CH341A programmer.

  1. Disassemble your MacBook and remove the motherboard from the housing
  2. Using hot air, remove the T2 ROM IC from the motherboard
  3. Using hot air, mount the T2 ROM to the T2 ROM reader board of your like (See our products HERE)
  4. Install the adaptor into the CH341A Programmer (or 1.8v adaptor if using solution that does not have the translation built in)
  5. Using a windows-based PC, open up the CH341A Programmer V1.01 software (you can download HERE)
  6. Click on the button labeled Auto Detect (25xx) towards the top of the program
  7. Select the chip version you are attempting to read. MacBooks from 2018-2020 typically will have either a Macronix MX25U3235F_1.8V or Adesto AT25SL321_1.8v chip.
  8. Click on the button labeled Read towards the top of the program
  9. Click on the button labeled Save towards the top of the program. Be sure to name the file something easy to remember with the original serial number somewhere in the file name
  10. Close the Program, then reopen it (due to software bug). Repeat steps 6 & 7.
  11. Click on the button labeled Read towards the top of the program
  12. Click on the Edit menu item list, then select Find. Search for the string BLM. If the first result does not look similar to what is pictured, then keep pressing F3 until you find the correct BLM reference.
  13. At this point, you should see your serial number. You can now change this to any serial number you wish
  14. Once you’ve change the serial number, click on the Save button. Be sure to name the file something easy to remember with the new serial number somewhere in the file name
  15. Click on the button labeled Auto towards the top of the program. You will get a prompt asking “Are you sure to program the chip automatically?” Select Yes to proceed. This will erase the T2 ROM, write the new ROM image, then verify the ROM based on the contents of the ROM file.
  16. Once finished, you should get a prompt stating “The chip as been verified successfully. All content are the same.” Click on the OK button
  17. Remove the programmer and adaptor. Remove the T2 ROM IC from the Adaptor and re-solder the T2 ROM IC back onto the MacBook motherboard.
  18. Load/Install macOS and confirm the serial number is equal to what you typed in the CH341A Programming tool



While this guide uses the CH341A programmer, it can be universally applied to other software as long as you have a basic understanding of SPI Flash programming. AsProgrammer is another tool you can use to work with the T2 ROM IC without issue.

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