Lets Study Pen Drives [ USB Flash Disc's ]

These Days Lots of Customers Are Coming With Thier Pen Drives For Data Recovery .Doing Logical [Software Based ] Recovery is Fine .But Lets share Info With Each Other When The Issue Is Actually The Electronics In The Drives .Are We Open To discussions On This Issue .I Had a Very Good Experience From 1 Pen Drive Today And Would Like To Share The Same IF You Feel We Need To Actually Talk On This Subject

Hi Amarbir,

I'm struggling with flash cards now, but i think the problem is about the same.
I've got the data from the flash eprom, but now i have to find out how the pictures are stored, and write some software to retrieve them.

I am searching for datasheets for the memory-controllers of flash disks and usb sticks, which would be a great help, but i can't find any.

Any help on this topic is welcome.

Best regards,

Dobre

Yes, i have two here I'm struggling with.

One is where the USB connector is ripped off and looks like damage the USB controller. On this one I think to transfer Flash RAM to donor USB stick, but need to confirm how to do this.

Another is seen as a device but 0 bytes. Last time I had one like this, there was loose connection on Flash RAM chip. a quick blast with Hot Air Gun, and was OK. This one is not the case. Do we think Flash RAM chip is cooked?

Cheers

Any input gratefully received!

Sean

Hi Sean,

Transferring the ram to another stick is not always a good idea since rams tend to get corrupted blocks and the controller then ignores them and uses a spart block of the ram, and also the memory is not addressed in a contiguous way since the controller tries to do a balancing of the write load so that every block of the memory is written to an equal times.

This info is stored in the controller. Therefore i would like to get the datasheets so i can study how they do it and where this info is stored (normally in the controller i guess).

Lots of work to do before we will have a solution to this.

Best regards,

Dobre

Dobre, I was thinking to put RMA chip on a USB stick with the same controller.

Surely the controller must store its info on the Flash RAM, as the controlller itself cannot store anything?

Just my thoughts

Thats why i need the datasheet! I've allready worked with many microcontrollers and it is not uncommon they have a small EEprom memory onboard.

Btw; how to resolder BGA's ? Are there any tutorials on the net ?

Regards,

Dobre

Hi Dobre,
I Got a Pen Drive From a Customer Yesterday And This is What I Did

1 :The Drive Was Totally Dead
2 :I Tinkered With The Electronics And Figured Out That Voltage To The Crystal Was Comming But there Was No Frequency Generation
3 :I changed the Crystal And The Pen Drive MCU started To Tick
4 :The Drive Was Still Not Functioning OK
5 :I Soldered The Drive
6 :Tested Worked differently
7 :I again Soldered [ Worked Still Differently ]
8 :After Soldering The third Time [ It Worked Perfectly ]

Conslusion

1 :check The Crystal Always
2 :Very Imp Soldering Should Be Correct [ These Chinese Pen Drives Are Like Very Bad In This

Thanks for the explanation Amarbir.

In many cases the solerings of the ram are bad.

Recently i got a flash card that was broken in two pieces, just between the controller and the flash ram.


I tried to reconnect all traces but that was very difficult since some cracks were under the flash.
Finally i had to give up.

So i would like to have (write) a program that can reconstruct the data from the binary read-out of the flash.
Not so easy i'm afraid.

Dobre

Dobre,
This is Were I Would Like The Experts To Step In ,Anyone Having a Hardware And Software Solution So That We Can Take The Memory Chip Out Read The Memory And Then Analyse The Same And Extract The Data .I Think The [wiki]FAT[/wiki] ,FAT32 or The NTFS Should Not Have Anything To Do With This

Amarbir

Just my quick guess, as I had mostly mechanically damaged sticks on which transplanting the Flash chip(s) to equal pcbs cured the problem:
has anyone yet checked whether the data is simply written linearily like on a LBA hard disk device and can therefore be recovered by any FAT32/NTFS/... data recovery software that is able to deal with image files of raw devices?