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eMMC fix?

OP saranhai

21st July 2011, 07:57 PM   |  #1  
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i think i might have found a possible fix for the eMMC corruption.

credits go to 3p4145 for discovering this:
Quote:

Well I am in no way an expert or have enough knowledge to find an answer.. but I have some basic idea... so here it goes...
If I understand correctly, the problem is that the eMMC driver chip gets corrupt...
This chip controls the MMC0 which is (part of the chip) the actual flash upon which the phone relies to store its stuff...

No Since the issue is seen with rooted phones more often, I would imagine something that was written to the mmc0 is causing issues.. Using root explorer, i found this file on my /proc/emmc

This file seems to have the some sort of memory locations for various directories on the mmc... a corruption of this file could be a bad thing... I am not saying that this is the cause.. but if anyone with a bricked phone could get into their FS (i have no clue how) and check this file.. we could look into coming up with a generic file with memory address that are common....
Mine seems to have locations address for:

misc
recovery
boot
system
cache
userdata
devlog
pdata

as he stated, the eMMC files that might be corrupted in the failed eMMC chips are located in /proc/emmc.
i have been able to get to this location using adb
Code:
cat /proc/emmc
so, would it be possible to copy the correct files from a good chip to this location, and fix the failed eMMC problem?
the failed chip's filesystem got corrupted i think (correct me if i'm wrong)

i have the emmc file, pm me if you want it.
Last edited by saranhai; 22nd July 2011 at 06:11 AM.
21st July 2011, 08:25 PM   |  #2  
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seems like a good theory. let's say you do copy the files from a good chip over to the bad emmc...how could you simulate or know when/how the M4G2DE 2.10GiB units would fail?
21st July 2011, 08:34 PM   |  #3  
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Quote:
Originally Posted by suchavibrantthang

seems like a good theory. let's say you do copy the files from a good chip over to the bad emmc...how could you simulate or know when/how the M4G2DE 2.10GiB units would fail?

it's impossible to tell when the chip will fail. but when they do.. could someone try this?
21st July 2011, 09:14 PM   |  #4  
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So it's a software failure and not an actual hardware failure? I'm not sure how likely this is to solve the issue, but any movement towards a solution is a good thing.
21st July 2011, 09:36 PM   |  #5  
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Quote:
Originally Posted by TeeJay3800

So it's a software failure and not an actual hardware failure? I'm not sure how likely this is to solve the issue, but any movement towards a solution is a good thing.

it's more of a firmware issue. inside a computer, there are many different chips. some chips are consisted of firmwares, these are the ones that you can write to and change (like the eMMC chip). other chips, are completely hardware, you can't write to them, you can't change them.
so since the eMMC chip is consisted of "software", then maybe we can replace the corrupted files with good ones.

but i need some testers, since my dead eMMC chip is somewhere in tmobile's dead phones junkyard.
21st July 2011, 10:08 PM   |  #6  
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If it's the chip itself that fails - then you can't fix it by writing something to it, since it won't write whatever you're trying to write to it. Trying that would be equal to trying to fix a failed hard disk by using it.

"Firmware" is just another term for software. No chip consists of firmware, firmware is written on memory (permanent or rewritable), which is read by some hardware (usually some type of CPU) that executes this firmware. eMMC is just a rewritable memory chip, and if the controller of the chip fails, or big chunks of the memory in this chip fail - it's not usable anymore.

And of course, there is no such thing as "driver chip". Driver is a program, software, that runs on CPU and is stored in - again - memory. eMMC controller, on the other hand, is hardware, a part of the chip itself. The failure is on a whole another level.
Last edited by Jack_R1; 21st July 2011 at 10:14 PM.
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21st July 2011, 10:29 PM   |  #7  
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Quote:
Originally Posted by Jack_R1

If it's the chip itself that fails - then you can't fix it by writing something to it, since it won't write whatever you're trying to write to it. Trying that would be equal to trying to fix a failed hard disk by using it.

"Firmware" is just another term for software. No chip consists of firmware, firmware is written on memory (permanent or rewritable), which is read by some hardware (usually some type of CPU) that executes this firmware. eMMC is just a rewritable memory chip, and if the controller of the chip fails, or big chunks of the memory in this chip fail - it's not usable anymore.

And of course, there is no such thing as "driver chip". Driver is a program, software, that runs on CPU and is stored in - again - memory. eMMC controller, on the other hand, is hardware, a part of the chip itself. The failure is on a whole another level.

You summed up my thoughts on the issue perfectly, especially the first paragraph. That's why I didn't understand why the OP's theory would work. I'm not knocking his efforts at all...anyone trying to fix the eMMC issue is doing a good thing, it just didn't make sense to me.
21st July 2011, 10:52 PM   |  #8  
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oh...
sorry.. i thought the chip was just corrupted when it said "failed"...
well then nevermind, this wouldn't work.
22nd July 2011, 04:08 AM   |  #9  
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Thanks for talking abt this guys..
I understand what you guys are saying.. but quite often the HW itself is not bad but the address locations are corrupt.. Like I mentioned in my initial post... I am not sure what causes the fault.. but Once caused, IF there is a way to just re-write the addresses for these locations so that the driver chip/Controller chip can try to use the addresses provided is what I am trying to see..

This statement is right on the amrk: "eMMC is just a rewritable memory chip, and if the controller of the chip fails, or big chunks of the memory in this chip fail - it's not usable anymore."

now considering this, IF the controller is physical fault (as in fabrication fault, overheated transistors etc).. the nothing more can be done.. BUT if the fault is just in the addressing fail.. this providing the addresses should work wouldn't you think?

If someone has a brick on their desk they can try this.. Nothing really to loose right?

I would never suggest replacing the emmc file of a working chip.. now thats just crazy talk.. well if you have $500 to spare.. sure.. but I was thinking of fixing a broken one...


One more last thing: The only problem with this approach on a dead phone is getting access to the FS AFTER the phone is dead.. any ideas?
22nd July 2011, 04:13 AM   |  #10  
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Quote:
Originally Posted by 3p4145

Thanks for talking abt this guys..
I understand what you guys are saying.. but quite often the HW itself is not bad but the address locations are corrupt.. Like I mentioned in my initial post... I am not sure what causes the fault.. but Once caused, IF there is a way to just re-write the addresses for these locations so that the driver chip/Controller chip can try to use the addresses provided is what I am trying to see..

This statement is right on the amrk: "eMMC is just a rewritable memory chip, and if the controller of the chip fails, or big chunks of the memory in this chip fail - it's not usable anymore."

now considering this, IF the controller is physical fault (as in fabrication fault, overheated transistors etc).. the nothing more can be done.. BUT if the fault is just in the addressing fail.. this providing the addresses should work wouldn't you think?

If someone has a brick on their desk they can try this.. Nothing really to loose right?

I would never suggest replacing the emmc file of a working chip.. now thats just crazy talk.. well if you have $500 to spare.. sure.. but I was thinking of fixing a broken one...


One more last thing: The only problem with this approach on a dead phone is getting access to the FS AFTER the phone is dead.. any ideas?

using adb you are able to get into the filesystem...

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