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Secret Of Recovering Data From Defect USB Sticks

By on February 4, 2020
usb repair

Today’s USB memory sticks have made a lot of media obsolete, including the old but trusted floppy drive. And memory stick data capacity keeps on growing bigger by the day with no end in sight. And increasingly faster data reading and writing speeds are now even making cd-rom and newer dvd disc look old.

But it happens that the memory stick no longer is recognized by any computer we try. And with it we lose all access to data that was stored on it. If this happens to a dvd we often can recover all or almost all previous saved data easily with programs like Isobuster. However recovering data on memory sticks is not that easy because there are a lot of facts we need to take in consideration before we succeed in recovering any of the saved information.

Here I will name a few of those reasons :

  1. When the USB memory controller on the USB stick is defect or its crystal, at best we should replace the controller or the stick by a new good working controller, because another controller from another stick won’t work!
  2. The data is saved on a Nand (flash) memory chip in a manner that is controlled by the controller it was attached to. Crc checks and page and memory bank addressing is used depending on what controller is used.
  3. Even if we succeed in reading out the entire stick’s nand memory bank or banks into one large bin file, which is easy with the RT809H universal nand memory programmer, we still can’t see any of the original saved files. We only see binary numbers or hex code we can’t interpret without knowing how the controller arranged that data. There is a good Russian site that knows all about every stick on the market but it takes a lot of reading to comprehend all that is written on that site about recovering. And not only because it is in Russian.
  4. Although the nand and the data that was stored on it could be gone too, in most cases the nand or nands (if larger sticks are involved) are still intact. These USB memory chips are mostly 2 x 24 pins (48 pins_ 8 or 16 bit) nands or newer bga chips. But we need to take special action to recover back the data that is stored on it in its original format. (Photos, Text, exe, html files etc.)

Now that we know the most important facts we will start with recovering all files from a now 4GB defect Sandisk stick with a bad FC8708 (square 48 pins type) controller chip. These controllers not only control the communication between USB and the Nand, but also the 5V voltage conversion to the voltage that the nand requires (1.8V or higher). Below a photo of this controller and the nand.

nand ic in usb

The nand was easily removed with hot air by just turning the chip downwards until it fell off the board without any real force. Of course without removing any of the other components on the other side of the board. And I checked and read the entire chip with the RT809H in a few seconds and saved the entire 4GB data file as bin file to my computer as a precaution in case the chip would fail later on. It was auto verified being okay! Which confirmed the nand was still fine! Next the screenshot from the RT809H with verified good nand.

good nand chip

Following photos show the defect 4GB Sandisk memory stick with bad FC8708 controller.

The 2 photos on the left and the middle show the module before the nand was removed. And the photo on the right shows the memory stick after the 48 pins (2×24 pins) nand was removed. And although there exists Alcor software that helps repairing this and other sticks online, it didn’t help here to regain control on the stick and neither will it help to recover any nand data without destroying (formatting) it first in the process. Because as said the FC8708 no longer works which means a dead stick. We can however use the free and fine software tools like CHIP GENIUSv4.17, CHIPeasy v1.5.6.6 or others to get all info on inserted USB sticks if the marking on the controller is unreadable and/or if the stick is working but the case still unopened. Those tools do not even need to be installed to work. Or tools like Flash Extractor that all require additional knowledge.

But of course Chip Genius and others only show all info on good working sticks. So in this case we will need extra tools and/or hardware to recover all data from the extracted nand chip.

nand chip repair in usb

Next picture shows the way in how the data in the bin file looks when it is checked with an hex editor. None of the original files are visible without the correct decoding that needs to be done by the now defect FC8708 controller to make any sense! (Or by an identical USB memory controller like the Alcor AU6987). So nothing we can use or do with our 4GB saved bin file without extracting and using the right knowledge from the special sites who deal with and collect data on all recovering all sorts of memory sticks. Those sites and sellers do have compatibility lists of controller chips and the nands they are able to control. So that is an other reason why recovering data on memory sticks is cumbersome. And some of those sites also show thousands of collected files with photo on every memory stick they archived. Often also mentioning the tools that were used to recover or repair the memory stick.

I tried to fix the defect FC8708 memory stick by ordering a new chip on Aliexpress but after payment and two weeks of waiting the seller without notice suddenly had cancelled the shipment. So I ordered that chip from another seller for twice the previous paid price but again after already two weeks of waiting the seller still hasn’t even shipped my chip. So I gave up on fixing the defect 4GB Sandisk memory stick.

rt809h program

To continue the task in recovering the saved nand data I therefore ordered another memory module without nand but including a special nand reader with a 48 pins nand test socket. That memory stick contains an in function identical controller chip being the AU6987 from Alcor. As could be read in instruction guides and lists from those sites. The AU6987 stick is inserted in the special USB connector on the nand tester/reader and with two 24 pins flat cable connectors connected to the nand tester socket. In which we now will put our to be correct decoded 4GB nand.

The hardest part was to solder the two 24 pins flat cable connectors on the AU6987 memory stick that is going to recover our nand. And the other two 24 pins flatcable connectors that are soldered on the nand tester reader at the solder side of the nand test socket. Because it were Diy kits that you need to solder first! Everything was ordered from Zirui shop who was patiently helping me with any question I had, and they did send me all guides and software (Alcor MP Tools which I didn’t need right now yet) until the recovery worked!

how to repair usb

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how to use rt809h

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save usb memory

Conclusion: After switching on the switch on top of the nand tester/reader the 4GB nand memory chip was perfectly recognized and finally saved to hard disk to the through USB cable connected computer.

All data was restored and rescued for the customer who’s original stick was dead. His original stick was still defect and maybe the ordered FC8708 will still arrive in a couple of weeks but no longer needed to recover the nand that still is fine but no longer is needed.

So recovery of defect USB memory sticks is very much possible if you order the right memory stick controller or controller chip and this USB2.0/3.0 nand reader/tester to make it possible.

This nand reader tester (about 34 euro including 9+ euro shipping), its board and the nand tester socket, which also is placed on a socket, is of very good quality, and can even easily be replaced with other memory bga sockets in the future. The AU 6987 memory module without nand and without 24 pins connectors did cost 10,42 Euro exclusive +9 Euro shipping. But taking in account what other firms dare to ask for such a recovery it is well spend money!

But if your soldering skills are not capable in soldering four small 24 pins flat cable connectors with only 0.5mm spaces in between, you better let someone else do it for you. It can be done as I did, but you need to repeat it for every other memory stick controller you want to use to recover the nand it in the past had written data to.

Although there probably is no other better way to recover the files of your lost memory stick, it isn’t cheap, and can only be done if you use the right controller or equivalent memory module.

So if you lost your favorite photos or important data, it just takes some investment and time to solder over 96 pins and components into the shown tester board to make it all possible.

albert from netherlands

Albert van Bemmelen, Weert, The Netherlands.

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Note: You can read his previous repair article in the below link:



  1. Lynn Blakely

    February 5, 2020 at 12:46 am

    Thanks Albert: For a detailed account of DIY recovery of usb3.0 memory stick. I will definitely subscribe to your blog.I save any of the posts here about computer repairs.

  2. Albert van Bemmelen

    February 5, 2020 at 12:42 pm

    Thanks Lynn, but the Blog is all Jestine Yong's, I only write my articles on his Blog. Glad that you liked the article!
    Keep in mind that recovery of USB sticks can be done easily with the Nand Reader if your stick has only one nand. And if it has two or more nands you still have to replace the controller chip of the memory stick itself like I wrote in the article. Why it is always advised to buy 2 identical sticks at the same time in case one of them fails in the future. In case that controller chip no longer is available you still can use the chip from your second bought memory stick. And even make another stick as expension for the nand reader with the two 24 pins flatcable connectors (after removing the not used nand from that stick). Or use the chip to fix your first memory stick with. Because there are too many different controller chips and also different nands! Why nands also often have different pin numbering which make it a real challenge to fix any bad memory stick. But fixing them is possible because the nands often are still fine like I wrote in the article! And they still have all the information that was written to them before the stick became a problem.

  3. Mason Sarles

    February 5, 2020 at 10:34 pm

    WoW, Thank you for your research and hard work. That was an education. Lesson learned, have backups of your back ups.....

    Thank you again for an excellent article

    • Albert van Bemmelen

      February 6, 2020 at 1:56 pm

      I was glad I could help my friend recovering the data of a customer this way Mason. See also my answer to your countryman Robert below with interesting links to forums and sites that help and dedicate in the USB memory stick datarecovery.

  4. Michael

    February 6, 2020 at 2:27 am

    Why didn't you just solder the nand onto an identical USB pen drive (swap the nand chips).
    I don't see the point in the nand reader other than for backup.

    • Albert van Bemmelen

      February 6, 2020 at 1:44 pm

      That is easy because we first removed the nand to test its content and its functioning. And we had no identical USB pen drive at the time. Neither could we repair the original stick so we chose a more universal method without having to resolder the nand too many times which is a big risk. And the seller who sold the USB 3.0/2.0 nandreader also sold a compatible AU6987 module we at the same time ordered to avoid the need having to resolder the not yet recovered nand. And this nand reader now can be used to recover many other FC8708 equivalent memory sticks without any risk. Or any different nand memory controller we assemble a new USB pen for.

  5. Robert Calk Jr.

    February 6, 2020 at 5:00 am

    Good job, Albert! I could not find a datasheet with those numbers. Our internet has been messed up today, so maybe google is messed too.

    • Albert van Bemmelen

      February 6, 2020 at 1:50 pm

      More info can be found on links like these Robert:
      and on
      Which helped to find a compatible controller and the solution.
      And the Russian sites like also this one help recovering data:

  6. Waleed Rishmawi

    February 6, 2020 at 4:08 pm

    I can say without a shadow of a doubt that i have learned something today I did not know before. thanks for sharing your experience and knowledge and have a blessed day

    • Albert van Bemmelen

      February 6, 2020 at 9:10 pm

      There is no day we stop learning my friend! We keep on shaking the tree of knowledge like in paradise. Have a blessed day too!

  7. Yogesh Panchal

    February 7, 2020 at 4:01 pm

    Albert. Nice Job!
    Have you tried ever Micro SD Card recovery for not detecting problem ?

    • Albert van Bemmelen

      February 7, 2020 at 10:44 pm

      No not yet Yogesh. But it certainly looks like those SD cards have the same sort controllers and nands in them. And SD card tools you can find for instance on:
      and an English manual on:

      • Albert van Bemmelen

        February 7, 2020 at 10:53 pm

        With this fantastic online translator program all Russian (or other languages) can be translate to the language of your choise for free!:

        • Albert van Bemmelen

          February 8, 2020 at 1:37 am

          See also this great website =>
          It also has SD card info!

  8. Albert van Bemmelen

    February 8, 2020 at 5:29 pm

    Look here for information that confirms that recovery of SD cards is in principle the same as with nands from USB memory sticks/pen drives:
    Success with recovering lost SD card data!

  9. Parasuraman S

    February 9, 2020 at 1:02 am

    Oh! My God! My head is reeling! It's too much for me! Though I did read the article! Hat's off!

    • Albert van Bemmelen

      February 9, 2020 at 4:22 pm

      There are a lot of tools for checking UFD (Usb Flash Drives) like USBDeview v2.3 and the already in the article mentioned tools that help reading the info on the controller and manufacturer of the USB memory stick/pen. Because often the it happens that the type markings on the controllers are different from what to expect. For instance a 48 pins controller with marking IDE S019SN-GT is according to the UFD tools an AU6989SN controller. Which I yesterday added to my in the article mentioned UFD nand reader. (after soldering two new 24 pins flatcable connectors onto the UFD controller board without any nand). Here a short list that I'm sure will help a thoroughly and accurate engineer like yourself to follow the compatibility conventions to make a successful nand data recovery.
      AU6992 = AU6985 = FC8508 (SC508)
      AU6990 = AU6987 = FC8708 (SC708)
      AU6987B = FC8708B (SC708B)
      AU6990T = AU6987T = FC8708T (SC708T)
      AU6990AN = AU6987AN = SC708AN
      AU6998 = AU6989 = FC8908 (SC908)
      AU6998L = AU6989L = FC8908L (SC908L)
      AU6998N = AU6989N = FC8908N (SC908N)
      AU6998NL = AU6989NL = FC8908NL (SC908NL)
      AU6998AN = AU6989AN = SC908AN
      AU6998ANL = AU6989ANL = SC908ANL
      AU6998AN-G = AU6989AN-G = SC908AN-G
      AU6998TN = AU6989TN = SC908TN
      AU6998SN = AU6989SN = SC908SN
      AU6998SN-G = AU6989SN-G = SC908SN-G
      AU6998SN-GT = AU6989SN-GT = SC908SN-GT
      And on the mentioned websites dedicated to data recovery we can find the compatible NAND Flash list for these controllers. Cheers!

  10. Andrea Del Corso

    February 15, 2020 at 9:33 pm

    Come sempre,un eccellente articolo!Grazie Albert.

    As always, an excellent article! Thanks Albert.

  11. Albert van Bemmelen

    February 17, 2020 at 4:40 pm

    Grazie Andrea per la tua apprezzata risposta. Questo articolo dimostra anche quanto sia universale il programmatore RT809H! Perché riconosce così tante nands e altri chip in pochi secondi automaticamente!
    Thanks Andrea for your appreciated reply.
    This article also proves how universal the RT809H programmer really is! Because it recognizes so many nands and other chips in only seconds automatically!

  12. davod amirajam

    April 27, 2021 at 7:24 am

    every alcor controler have a id
    how you know 45 d7 94 3 76 d5 =sandisk tc58nvg5d2fta20 =32nm 24bit ecc

    au6984-86=12bit ecc =exmple samsung intel 50nm (k9gag08u0m)
    au6987hl-6990 24bit ~30 bit ecc = your nand correct with 6990
    6989n 70 bit ecc 19nm d2 d3 ed3
    f500 =gtc 3d tlc support
    alcor very best in fix and found easy

    you can just pay 2$ and aliexpress au6990 and all you files is ok

    ca03 = is have so name but encode and decode is same

    example au6990n= no need 12mh crystal

    fc8708 =is ca03 = or ca02 is also work
    personaly i fix jetflash v700

    change au6990 =ic burn out
    i change it by fc8708
    nand is 32nm 4ce mlc sumsung *2 channel
    all files is ok
    flah also work

    just change 5 volt fuse and controllr
    in 90% 5 volt fuse change
    if controller stell hot must change

    in also phison 2251-68 i change it up23n
    all files is ok
    every flash have encrypt
    you use same controller
    if use other pcb is ok but pcb must for same controller

    i have broken 3257enba pqi= samsung 27nm ddr tlc
    i extract nand
    install on silicon power 3257enba
    and some jumper
    flash recovery is so expensive
    but in 90 % is no need special tool
    just same controller and pcb


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