I know that a previous post of mine talks about the infamous eMMC problem where the chip will burn out, however looking over some of my notes on eMMC chip problems I did come across a couple of things I noted in regards to possibly finding a solution to a couple of the issues.

 

Now the usual way we know we have an eMMC problem is that we get:

 

E:Can’t mount /cache/recovery/command

E:Can’t mount /cache/recovery/log

E:Can’t open /cache/recovery/log

E:Can’t mount /cache/recovery/last_log

E:Can’t open /cache/recovery/last_log

 

appearing as a debug message, this is actually the full “cache” partition being corrupted. Obviously the majority of rom chefs have run into this problem many times and myself included I have seen that message on more than one occasion over different handsets.

 

Usually there isn’t a fix for any error like that, once the cache partition is corrupted you really cannot recover from that, it is a catastrophic failure. The only way I have been able to fix this a couple of times and that was by immediately removing the battery and letting it sit for a couple of minutes before putting the battery back in.

Then if you boot directly into the boot loader and hit into recovery mode.

Now if you haven’t received any major errors you cahce partition should now be formatted as ext3, so if you cycle through the menus and format it to ext4.

Do a full wipe of everything, including factory reset, davlik cache and battery stats

Flash the rom of your choice again (now make sure it is the correct rom for the phone) and hope for the best that it works.

 

Now hopefully that potentially can resolve your problems, if not then you will probably have a serious eMMC problem and potentially will have bricked your phone.

 

I will say this method has worked 9 out of 10 times with me and I still have these notes saved for the next time it occurs.

 

Key things to remember, always track changes in the rom – see if there is a good user base and check them against other more popular roms to see the differences and benefits if there are any.

Usually you aren’t required to even think about the eMMC chip, what it does or what consequences a specific action has on it until you break it.

This is when things go wrong:

E:Can't mount /cache/recovery/command
E:Can't mount /cache/recovery/log
E:Can't open /cache/recovery/log
E:Can't mount /cache/recovery/last_log
E:Can't open /cache/recovery/last_log

Now luckily I’ve only ever had one failure of a chip and that was with a G1 which basically couldn’t take any of the re-building any more and just gave up. What I will say is that before you go jumping into anything regarding replacing the chip, or following another persons advice I would seriously read up on all that you can that is online. There are thousands of postings on the internet where people have had problems and been able to resolve them without having to take the phone apart and replace the chip.

Plenty of people have experienced what you are experiencing so the best port of call is to find a nice friendly forum (kind of hard to find now-a-days) and make a post detailing all of the issues.

Now what to do when you are posting all the information regarding the phone you have, model, age, firmware version. If you have adb set up on your computer – which I would expect you to have if you were flashing roms, what to do would be to enter into recovery mode, plug the phone into the PC, and open up a command prompt on the pc. Now you want to connect via adb to the device and once connected run


dmesg | grep mmc0


Now if the output contains this message:


mmc0: failed to get card ready
mmc0: reinit card
mmc0: Starting deferred resume
mmc0: Deferred resume failed


Then I’m afraid there isn’t much that can be done, if that set of messages rolls into your command window you are basically looking at getting a replacement chip. There are unfortunately no work a rounds to save you from this, no other solutions at all. Basically new phone or new chip – the choice is yours.

For the people that didn’t get that message, remember to post the output in your forum post and you may be able to save your lovely handset.