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[Q] eMMC crash - possible reasons and solutions

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By levantine, Junior Member on 28th November 2011, 07:03 PM
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30th November 2011, 12:48 PM |#11  
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Quote:
Originally Posted by amidabuddha

Just in theory when updating several apps from the Market (or other activities requiring use of /cache partition) it is possible that the /cache is filled with data and the device stucks at a point when it has no more space available to write. Rebooting to recovery and wiping /cache solves the problem. But if in that moment, when the app is downloading to /cache and another app is written from /cache to the /data partition at the same time, disconnecting the power source (battery pull) can interrupt the process making this partition unavailable (example: if you take out your USB flash drive from the PC while writing data on it there is a great chance to destroy it - tested myself ) The ext4 file system provides a protection for such cases by the way it is managing the writing process - reference here.

I agree with that. Most plausible theory i read about eMMC fries/corruptions. You've been helping people get out of this crap (i call it crap because it's HTC's fault, cheaping out on us) for a long time now.

What i don't understand is this - when downloading multiple apps from market (i had 2 - Angry birds, ES file explorer), the phone goes to sleep mode, and NEVER wakes up. No ADB, no 3 key combo, NOTHING. This leads to an unavoidable battery pull, which results in corruption like you said above. Why does the phone enter this "Sleep of Death" if you may call it? What the hell is the problem? Also, why not other HTC devices? (for that, i guess the answer is the unique slide out battery, only in 2 other devices - Bliss and Radar, whose battery can't be removed). If we can solve the "Sleep of Death" mystery, we'll get this issue out.
(More info - http://bit.ly/rXhDRR and http://bit.ly/v3lsS6 )

Also, DS (and all new HTC devices) are EXT4 by default. Flashing (not s-off'ing, but flashing a ROM after that) changes back to EXT3. That is probably why my phone survived the battery pull i did as said above. (It was freshly s-offed by XTC Clip, stock ROM).

Finally, i think this only happens to devices with already screwed eMMCs. Mine survived many battery pulls after the first one. The screwy ones are region specific. I never read anyone from India had the issue.
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30th November 2011, 03:28 PM |#12  
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Quote:
Originally Posted by shrome99

...Also, why not other HTC devices?

I am not quite sure...
Quote:

...Next I got on the phone with the HTC help center. I got friendly with the lady technician on the call. After some nice chat I started probing for information on the Desire S. After a long conversation She told me that the Desire S, Incredible S, Desire HD all have the problem of frying the eMMC chip if the battery is disconnected while power is on. She said she gets calls every day with people who have fried their eMMC chip...

Also
Quote:

The Desire S does not have a force shutdown keystroke combo as my old Desire did.
...
And because of a design flaw in the way the battery door closes, and because HTC did not include a force shutdown key combination to shut the phone off properly when locked.

The 3 key combo on Desire S performs a hard reset, 2 key combo boots to bootloader from a shut down state, but no combination for a force shutdown when powered on.

Taken from here

So from all the above is clear that the battery pull is the reason for this fault and I think that the deduction of the OP (post #1) is in the right direction, but unfortunately I do not have the required technical knowledge to comment.

For me the following is a must to avoid this problem:
  • always keep the USB Debbuging" ON in Settings
  • always disable "fastboot" option in Settings to prevent "hibernation" mode, i.e. running processes
  • keep your /cache clean (always wipe before installing anything)
  • stick to ext4 file system
  • if the device hangs anyway never pull out the battery, better wait it to be completely drained
30th November 2011, 03:40 PM |#13  
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The hard reset sucks. The one on my iPod touch ALWAYS works. You are stuck anywhere, hold home+power for 30 seconds, and there's a hard reset. This one rarely works
30th November 2011, 04:41 PM |#14  
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the snd time when my phone spoilt is when i accidentally pressed update all in market..
then the phone became sluggish and finally hanged.
as i've had experience and didn't dare to pull the battery,i used the hold buttons to restart method.I had to hold it for loonger time than usual(like 15 seconds ++)
after the phone's screen went oof,the phone never boot up again
30th November 2011, 05:35 PM |#15  
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Quote:
Originally Posted by tcchuin

the snd time when my phone spoilt is when i accidentally pressed update all in market..
then the phone became sluggish and finally hanged.
as i've had experience and didn't dare to pull the battery,i used the hold buttons to restart method.I had to hold it for loonger time than usual(like 15 seconds ++)
after the phone's screen went oof,the phone never boot up again

Wait, so you've "fried eMMC" chip by pressing Vol up+Vol down+Power only?
30th November 2011, 05:49 PM |#16  
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Hard reset while downloading apps = Cache corruption.


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30th November 2011, 06:40 PM |#17  
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OMG And i just got Desire S for myself. Now S-Off in progress, can't wait to see what eMMC chip i've got...

EDIT:



Feelin' lucky Going to format all partitions as EXT4 and flash CM7.
11th January 2012, 02:05 AM |#18  
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Quote:
Originally Posted by levantine

Hello everyone.
1) The faulty guy is usually Samsung eMMC-type BGA chip KLM4G2DE (2 Gb NAND flash), however Sundisk chips were also found to burn.
2) The problem is rather hardware than software dependent as it is observed without any corellation to hboot/flash installed.
3) It was noticed that in many cases eMMC fault followed extraction-insertion of battery after phone freeze.

Just leaving this here for Google'ability. I've experienced a similar case on a Samsung device, equipped with a MAG8DD moviNAND (manuf. date ~10/2009). After pulling the battery the moviNAND died.

Code:
mmcblk1: mmc1:0001 MAG8DD 15.3 GiB
mmcblk1: error -110 sending status comand
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9th February 2012, 03:24 PM |#19  
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bumping for more attention.
9th February 2012, 11:50 PM |#20  
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one more theory :

emmc has internal voltage regulator, that requare external decoupling capacitor.
from sandisk inand datsheet:

VDDi Connections
The VDDi (K2) ball must only be connected to an external capacitor that is connected to VSS. This signal may not be left floating. The capacitor’s specifications and its placement instructions are detailed below.
The capacitor is part of an internal voltage regulator that provides power to the controller.
Caution: Failure to follow the guidelines below, or connecting the VDDi ball to any external signal or power supply, may cause the device to malfunction.
The trace requirements for the VDDi (K2) ball to the capacitor are as follows:
• Resistance: <2 ohm
• Inductance: <5 nH
The capacitor requirements are as follows:
• Capacitance: >=0.1 uF
• Voltage Rating: >=6.3 V
• Dielectric: X7R or X5R

maybe there's PCB design problems (inductance), or too small capacitance of decoupling capacitor in DS ?
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13th February 2012, 07:42 AM |#21  
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Quote:
Originally Posted by olyloh6696

Also, strangely, a common way to trigger the 'dead emmc' is when you hit 'update all' apps in the android market, regardless of what ROM/market version your on..

Surely it must be a combination of a software fault/problem too?

owh is it...
now wonder mine seems kaput already.
keep on restarting with the eMMC in, but ok after i take it out.

BTW, is this eMMC covered under warranty? as it cames together during purchase last time.
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