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 Post subject: SD card rescue - DIY?
PostPosted: July 21st, 2018, 16:21 
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Joined: July 21st, 2018, 16:08
Posts: 5
Location: earth
So my daughter's 8GB SDHC card (Intenso, Class 4) has died, and along with it her last two years of photography memories....

When inserted into a Windows machine (tried four different machines with different card readers), the system can barely detect the card (but it will not show up as hard disk) and diskmanager reports the correct size, but other than that, diskmanager only sees unallocated space. Eventmanager reports hundreds of errors, some mentioning controller errors.

I tried various utilities that claim to be able to recover low-level data, including some command line tools on a Linux machine (TestDisk, PhotoRec) which took a full weekend to recover zero bytes. With that, it seems likely that there is a hardware error.

I started to read up on such things and found people that unsolder the NAND chips to bypass the possibly broken controller and then read raw data from those and assemble files eventually. Unfortunately, they charge around 150-200 bucks, which is a lot of money for us.
Then I realized there are NAND flash readers for about 100 bucks (such as this one) - and now I wonder whether I might spend about the same amount of money if I do it myself - but then I have also learned something new!

Any thoughts or suggestions on how to proceed with that?

Thanks!


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 Post subject: Re: SD card rescue - DIY?
PostPosted: July 22nd, 2018, 3:35 
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Joined: December 4th, 2012, 1:35
Posts: 3844
Location: Adelaide, Australia
"Earth" is a large sphere. Recommendations for a lab would be possible with a realistic location in mind.
The brand "Intenso" wont help, the controller and NAND chip combination is more useful, or if it is a monolith or not.
If you have already tried the Data Recovery tools, then a Lab is all I will recommend. You may be able to troubleshoot the PCB for electronics if you open it up (carefully) but I am not going to recommend it.

you could try using DMDE to create a full disk image, cancel any prompts until the disk shows up and right click disk (not partition) and create a clone/image. If you get I/O error, your best bet is a lab.

Data Recovery is expensive because it is hard and time consuming. There are many many factors to a successful case. Tools are expensive. Takes a lot of experience. No-one likes charging hundereds for a 10 dollar drive recovery but it is a must.


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 Post subject: Re: SD card rescue - DIY?
PostPosted: July 22nd, 2018, 3:58 
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Joined: July 21st, 2018, 16:08
Posts: 5
Location: earth
Thanks for the comments! I realize it has to be expensive and definitely do not try to dismiss the effort needed (I watched a bunch of slightly intimidating videos showing the process), it's just tricky to decide whether hundreds of sometimes shaky, blurry vacation pictures of my daughter are worth it. So I wondered whether I could make it up with some of my own time instead of money.
I am located in Germany - any recommendations for a recovery lab would be appreciated.

Not sure how to get to the controller/NAND chip combination/monolith info without breaking the card open, something I have been holding off until now. The card also has a bunch of small black letters lasered onto the backside, looks like a serial or batch no. but googling that did not bring up anything.

I have not tried DMDE yet, but will do so as soon as possible and report back.

Thank you
Martin


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 Post subject: Re: SD card rescue - DIY?
PostPosted: July 22nd, 2018, 4:45 
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Joined: July 21st, 2018, 16:08
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Location: earth
OK, just tried DMDE:

It finds the card (and shows a size of 7.74 GB, with sectors 0 - 15 126 527), but then I get this error:
LBA: 0 (try 0): WinError 1110. The media in the drive may have changed.

On Retry, I get the next error:
LBA: 0 (try 1): WinError 23. Datat error (cyclic redundancy check).

This repeats. So I chose Ignore to see what is coming next and I get more WinError 1110 messages, with increasing LBAs.
The hexdump in the main window all shows 'BAD'...

Rt-clicking on the disk and imaging brings up again WinError 1110, this time to the highest LBAs, mixed with WinError 23.


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 Post subject: Re: SD card rescue - DIY?
PostPosted: July 22nd, 2018, 4:46 
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Joined: December 4th, 2012, 1:35
Posts: 3844
Location: Adelaide, Australia
if you don't trust splitting it apart with a hobby knife, a safe method is using 220grit or so sandpaper and sanding the edges. The goal is to make them thin so it easily breaks the shell apart.

The shell is in 2 halves, and is sonically welded. when you open it you will either have a monolith ( a single all in one chip) or a PCB with controller, NAND chip and some discreet electronics.

photos of that would be useful, though a homebrew solution is unlikely.


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 Post subject: Re: SD card rescue - DIY?
PostPosted: July 23rd, 2018, 11:12 
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Joined: July 21st, 2018, 16:08
Posts: 5
Location: earth
OK, thanks - I will give that a try. At least that will safe the professionals some time (unless I create additional damage ;-)


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 Post subject: Re: SD card rescue - DIY?
PostPosted: August 25th, 2018, 18:01 
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Joined: July 21st, 2018, 16:08
Posts: 5
Location: earth
Just in case someone is following: I was travelling the past weeks, so no progress so far (and the card is still inaccessible...)
Now I am back and will have time for this again in a few days.


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