Oh OK. I believe Thaiphoon Burner (paid version) can write SPD data to the DIMMs assuming the Bios allows SPD Write. I recall people using this to un-brick DIMMs that had corrupted SPD data that was caused by G.Skill's RGB control program in the early days of RGB RAM. It's not clear to me why OP would want to change a DIMM serial number. I suspect that you know way more about this than me so I will defer to your expertise.