7035 Internal and External storage unmounted

[Saithies]

Hi all, I'm new here. I hate my first post being such a difficult problem but I and about ready to junk the tablet. I run a recycling center and I got this tablet from an elderly man. He only used it to browse the internet and read books. He said one day all his books just disappeared and he was unable to get any SD card to be recognized. The music app says the storage is busy. If i plug in a USB cable (with or without the SD card installed) the circle icon showing the USB is connecting never stops spinning and neither the SD card or internal storage are accessible on the PC. I did a software factory reset AND a recovery factory reset. Neither made any difference. I began to think the SD card slot was broken until I copied some files to the SD card using my phone. Then booting into the stock recovery on the tablet I was able to browse and open files on the external SD card. It appears as though I can also access the internal storage while in recovery but with no files there I can't be 100% sure. So it looks like a software issue. I've seen several other threads with similar issues on this and other Coby tablets, but no solutions that worked for me (maybe because they had a different tablet?) I found some one's MID7035-4 dump here on this forum but I have no idea if I can even use it. I've rooted a few phones and tablets, flashed CWM or similar, and installed custom ROMs but that is really the extent of my Android knowledge. Thank you in advance to any an all help. It is very much appreciated!

Please note: I do not have ANY of the tools like ADB or busybox currently, so if your advice requires me to run a tool or command that uses a tool please tell me what to download.

 

[Saithies]

UPDATE: I believe I got it rooted with SRS root. Since I have NO storage on the device I cannot install apps like root checker to verify. I found some posts about vold.fstab and build.prop I'm wondering if mine are corrupted or something. How would I go about opening them and posting them here?

 

[Saithies]

UPDATE 2: I attempted to use Vampirefo's walkthrough on root, recovery and unsecureboot.img for the 7033 located here. Maybe it's not working because I have a 7035 but a lot of people keep saying it's the same tablet only with different touchscreens. The unsecure boot seems to work because, debugging does not turn off after restarting the device. However, I cannot get ADB to see the device while in recovery even though windows loads the driver the same as when booted into the OS. If I can get ADB to see the device maybe I can flash a dump to it and see if that fixes the problem. The only errors I saw while using vampirefo's instructions were about not erasing 2 bad blocks

 

[Saithies]

Update 3: I tried using ADB push to rewrite vold.fstab and build.prop using files from a dump but that did not change anything. Since I can't browse the files on the phone I don't know if I even did it right. ADB kept saying it transferred either too many KB's or too few. For example: build.prop from the dump is 2kb but adb said it pushed 166kb. Running the command again it says it pushed 1kb. So I really think I need to flash the entire dump somehow....

 

[kevinthefixer]

Are you sure you have a stock recovery? I've not seen a stock Android recovery with a file browser before. You will need a custom recovery to flash any dumps, so I'd check carefully. Make sure your tablet is not subject to "nand lock" before flashing anything. I would recommend you stop fooling with system files until you've done a lot more reading. Most of what the world knows about Coby tablets is in this forum...

 

[Saithies]

If its not the stock recovery I'd be shocked since it has almost zero options. 4 to be exact. Factory reset, and wipe cache are 2, the others are not file browsers they say update from sd card and update from cache. Using either option I can browse the folders and see some files on the SD card. There are no files or folders in cache as far as I can tell. Yes I would love to stop messing with system files but all I can do is read and try stuff out since this particular model doesn't seem well supported. Other people seem to have this or similar issues with SD cards and internal storage. Everything I have tried so far was pretty much recomended or attempted by some one else on this forum somewhere. It's not like I opened vold.fstab in a text editor and just started typing code. I used legit files from good dumps.

I have no idea what nand lock is. I get the idea since the OS is installed on NAND memory but I don't know how or why that being locked would cause my SD card to act like this.

 

[Traveller]

Coby implemented the nand lock as a means to curb warranty returns of its tablets caused by certain badly written custom ROMs. These ROMs are not found on this forum and are easily recognized, as you have to BUY them. Needless to say, Coby had to do something.

The nand lock triggers whenever a custom ROM or custom recovery is installed. It is also triggered whenever vold.fstab is modified — usually to enable read/write access to the MicroSD. What it does when triggered is to remove access to the internal storage, essentially making the tablet useless. Rooting the tablet is still possible, but the nand lock ensures that modifications to system files do not occur.

If you can still see files in internal storage, it's unlikely you have a nand lock. When the nand lock is triggered, the internal storage completely disappears. By your descriptions you don't have that problem. However, I wouldn't be so quick to dismiss faulty hardware as the source.

 

[Saithies]

Traveler, thank you for the info about the NAND lock. Somehow, I can now install apps on the internal memory but the SD card is still only viewable in recovery. I've been doing electronics and computer repair for over 15 years. I know the difference between hardware failure and software failure. I can repeatedly access the SD card using different software (recovery) but not another (OS). This could mean the SD card slot has become read only since I have been unable to test writing to the SD card with the tablet but if there was not something wrong with the OS I should still be able to at least read data there. If it was hardware failure it wouldn't matter what software I was using I would not be able to access the SD card. Traveler I also see that you tell a lot of people it's probably hardware failure but you don't really help them much in the way of troubleshooting or figuring anything out, and that's OK because it could be hardware failure many times but doing what I do for a living I absolutely LOVE it when people like you tell my customers things like that and they bring me perfectly good devices for recycle. That's how I got my 56" television, my PS3, my xbox 360 and my phone among other electronics over the years. Electronics are almost always fixable if you have the patience to try and a little know how. What I'm lacking here is the know how and that's why I am on this forum but so far what I'm getting from you guys is pretty much just to give up on it. I'd rather not because if we can figure this out we can help other people having the same problem.

 

[Traveller]

Most people don't have the patience or the knowledge. I do have some knowledge, but no longer have the patience. One variable you don't mention is time, which is something I don't have a lot of.

As to my telling people it's a hardware fault, you're right. I often say it, and I don't help people out, because to really do that I would need to have the item in my hands. At the same time, I'm not a technician, but someone that has done his best to keep up with advances in hardware over the years. In short, this is a hobby to me, not a job.

My word is NOT gospel, and I put on my pants every morning in the same fashion everyone else does.

 

[vampirefo.]

What you need is the mount layout of a working 7035, you would then use busybox via adb to format and then remount internal sdcard as vfat.

sent from my kingSing T1 via taptalk

 

[kevinthefixer]

What you need is the mount layout of a working 7035, you would then use busybox via adb to format and then remount internal sdcard as vfat.

Could that be done via CWM, assuming CWM can be installed on this tablet?

 

[vampirefo.]

Could that be done via CWM, assuming CWM can be installed on this tablet?

No, must be done from desktop mode, recovery mounts are different than desktop mode.
Also this method is to repair software not hardware.

sent from my kingSing T1 via taptalk

 

[Saithies]

What you need is the mount layout of a working 7035, you would then use busybox via adb to format and then remount internal sdcard as vfat.

Where can I found the mount layouts? They should be included in the dumps posted here correct? I'm also not familiar with how to do what you're talking about. Any chance you could help me out with the scripts please? I can probably find them myself but knowing my luck it would be for a different tablet or OS and mess things up. I'd be happy to donate for your time. Thanks!