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Old 02-17-2015, 08:35   #14 (permalink)
serviceman28
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Quote:
Originally Posted by rfearn View Post
I have downloaded several eMMC chips Samsung S2 and HTC one using ISP and also direct eMMC via chip off and I am seeing a strange behaviour.

Each time I read the chips, a pattern of repeating 128 bytes is XOR'd with the data. This pattern is repeated about 20 times then again several tens of kilobytes later all through the file. For each new read of the chip a different 128 byte pattern is found

This means the data read from the chip cannot be used to extract the files we are looking for.
I have tried changing chips but always a random pattern appears in the data.

I have tried newer releases of he GPGeMMC software but the same result.

It is not a problem with the chip as reading it via a different memory reader we borrowed read the chip fine without errors.

Is there any thing I can try to fix this problem?

The only work around I have found is to read the chip 5 times and for each byte take the most common value at that offset (usually 4 is the same and one is different).

Sample parts of memory reads are below:

Read1

0000FF00000000000000000000000000000000FF0000000000 0000000000000000000000000000000000FF0000FF00000000 00000000000000000000000000FF0000000000000000000000 0000000000FF00000000000000000000000000000000000000 00FF000000000000000000000000000000000000000000FF00 0000000000FF00000000000000000000000000000000FF0000 0000000000000000000000000000000000000000FF0000FF00 000000000000000000001902736563758D65000B0203190273 656375726501540BFE03190273797374656D3712EB1D4A5100 00000153AE4C69746520666F726D6174203300100001010040 20DF000037FB0000FF00000000000000000000000009

Read2
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

We recently bought a box and we have exactly the same problem.
is the solution?
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