USB memory recovery

[eripaha]

I am learning to repair badly damaged USB memory sticks. So far i have replaced damaged USB connectors and been able to read data off even USB sticks with pcb broken. As long as the NAND chip is not damaged is it possible to lift the NAND chip with rework heat gun and place it into to another identical donor memory stick?

Can you identify the smaller chip in these pictures?

I plan to try this out with two of my Kingston DataTraveler 100 G2 8gb sticks if there is no fundamental problem in this.

[mikeselectricstuff]

Should work unless the control chip has some of the bad-block map stored in it.

[marshallh]

Like you say it should work in theory but I've attempted that twice with exactly identical pcbs/controller chips with no luck. Might be more to this than I know.

[codeboy2k]

I have no specific knowledge, but I would think that the bad block map is stored on the flash memory itself, but the controller only stores the block number (or page) of the bad block map (which is determined at first power-on).  This allows identical firmware to be flashed into the controller, and it can scan the NAND flash that was assembled into the board and find a reliable area to store the bad block map itself. 

Then the firmware can report back if it found 1G, 2G, 4G or 8G of good memory.

However, in this scheme, after first power-on, the NAND and the controller are now married.

[homebrew]

Yes, it can work.

I have done exactly that procedure with a broken USB stick. It worked perfectly!

I didn't even had a rework station, I had to use an ordinary heat gun and a temperature probe ...

The guy who gave me that stick wanted to get the data back but refused to invest a lot of money into a professional service.
Whether or not you should try such procedures depends on the value of the data ...

Cheers,
Peter

[amyk]

Can you identify the smaller chip in these pictures?

SSS 6696

http://www.usbdev.ru/files/sss/
http://www.3system.com.tw/en-global/product/productDetail/60#

There isn't much info on it, but for some reason the Russians seem particularly interested in playing around with USB drives... as you'll see if you Google "SSS 6696". The controller does have internal flash and firmware so it might not be as easy as a chip swap.