How to unlock a locked memory SPD.

I wanted to reply to this thread: http://forum.notebookreview.com/threads/how-to-flash-ram-spd-when-it-seems-to-be-read-only.408349/

The OP @moral hazard was trying to figure out how to unlock the SPD EEPROM of locked modules. Some are unlocked, which allow you to use software like SPDTool or Thaiphoon Burner to change any of the data stored in the EEPROM. However many are locked and, unfortunately, once the EEPROM is locked it can no longer be unlocked. The only solution to a locked SPD EEPROM is to remove it and solder in a different one that has not been locked. Yes, it works. I just got done doing it and it is easier than it sounds.

First of all, the only way to know if the SPD EEPROM is locked or not is to attempt to flash it. Thaiphoon Burner says that it can tell if it is locked or not, but it can't. If the chip is unlocked and not lockable, or if it is locked, it will look the same. Also if you flash with Thaiphoon Burner, it will say everything went well even if it was unable to write to the EEPROM. You need to look at the SPD information to see if it was actually changed or not. SPDTool will write and then it will see if the changes were made. If any errors come up, it means that the SPD EEPROM is locked.

The EEPROM chips used on DDR2 memory modules are always easy to remove and put back. A wide soldering tip to desolder each side at once, and then a fine tip to resolder each pin separately works very well. When resoldering, use a piece of kapton tape to hold the chip in place.

The EEPROM chips on DDR3 modules are usually of a smaller package type than DDR2 modules. However, they should function identically. The PCB's of all but one of the 9 DDR3 sticks I have on me right now have pads to solder either of the EEPROM chip sizes to them. A soldering iron can solder on one of the smaller chips without much trouble, but it cannot desolder it without destroying it. This is fine if you have fresh new loose EEPROM chips to use. If you need to remove one of the small chips without damaging it, you can use hot air. I recommend using the larger EEPROM chips to solder on if you have a choice. You can use the EEPROM chips from DDR2 to use on DDR3 if you need to.

If you soldered on a new or old EEPROM chip without being able to first flash it with the new memory profile, it doesn't matter. Boot your computer with a working stick of RAM and one memory slot empty. After the computer loads the operating system, you can install the non-working memory stick into the empty slot and then flash the EEPROM. If you are removing the EEPROM from another memory module, I recommend flashing it with the SPD information that you want on it before desoldering it, as it saves you an extra step later.

I hope this helps someone looking to do this and puts aside some fears. I just got done doing several desolderings and resolderings, and nothing was damaged. Just be careful, take your time, and inspect the solder joints visually with a magnifying glass or digital camera and electrically with a multimeter. Good luck!

 

Looks like you could use a hot air rework station...

 

Why? I do have one.

 

Oh, I thought you didn't since you mentioned using the wide top for de-soldering. Figured mentioning one might help others trying to do one.

I don't have one but we've got one at my office.


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By "wide," I don't mean very wide, just relative to the fine point I used to resolder each leg individually. Those four pins you see in the picture are just 2mm across.