Sd Card Mount Point modification discussion. Post-Root

[marvin02]

You make this mod at your own risk. What worked for other users may not work for you.

Now that we have root there are a few ways to attack the SD card issue.

As far as the sd card there are probably a couple of options.

1) A symlink that makes the external card appear to the system at /sdcard. I am not sure what this does with the internal storage.

2) Modify how the system mounts the internal memory and mount that at a different mount point and then mount the external sd card at /sdcard. I think this might be the best way to go. It would open up using the internal memory for another use. On some devices with a similar stock setup to the VTAB the only option that worked was to swap the mount point as the system wouldn't accept other solutions. I am not familiar with the details.


I suggest that some thought be put into this so that no one ends up with an unusable device.

There is also the possibility of addressing individual apps by creating symlinks.

Let's discuss options and what is tried/tested in this thread.

Research into how others devices deal with this is my next step. Fell free to dive in.

Some reading:

• Info on data storage from Android Developers
• Info about app install locations from Android Developers

NOTE:

This post (in this thread) has details about making the mod to swap the mount points of your internal storage and the user installed SD Card. Read the whole thread before proceeding.

Warnings:

1. Stuff may run slower - using the best external SD Card you can afford will help here, but it will never be as fast as the internal storage.
2. If you remove your external SD Card any apps that are located there and any data there will not be available.
3. You may have to reinstall some apps.
4. You may void your warranty.
5. You may brick (ruin, mess up, break) your device.
6. There may be other side effects that no one is aware of yet.

DO NOT use the Unmount SD Card from the device settings under SD Card & Device Storage.

DO NOT format either the internal memory or the user installed SD Card using the device's settings menu.

You make this mod at your own risk. What worked for other users may not work for you.

SD Card & Storage page after mod (please view!)

I have attached my original and modified fstab files in the zip below.
Zip of both the modded and original fstab files.

[Sponsors]

[rprr]

Here is what I find when I run the following commands. Please see attached files.

# mount
# cat /proc/partitions
# cat /cache/recovery/last_log

Hope this is useful.

[marvin02]

Something to chuckle at in this thread. See the "solution" posed in the fourth post? The second post in the thread is a nice summary of how some newer Android devices use internal storage to mimic an external sd card, like the VTAB does.

Back to searching. . . . . . . .

[shawnph]

I got it working. But I'm now trying to make sure the internal memory is also available. I have it only seeing the external card and not the internal space. Instructions will be forthcoming once I get the internal card space back available again.

[marvin02]

Did you edit vold.fstab and try switching the mount points? I wondered if that would work, but was trying to research other devices and see if issues crop up.

In your modified system what output do you get from the mount command?

[nb45cl]

Instructions to mount the external SD Card as the default sdcard on the Vizio VTab. How to overcome the 2gb limit.

Root is required for this to work. And you need an SD Card in the slot, of course.

NOTE: This is the first go at the instructions. Using these steps, the external card will be visible to the Vizio VTab The internal card will not until someone figures out what else to change. Make sure to copy all contents of your internal card to the external as part of this process.

CAUTION: You probably should know a little about linux before doing this. Be very careful. Do this at your own risk. It probably voids the warrantee. But if you've already rooted your Vizio, that probably voided the warrantee first.

** End of disclaimer **

First make sure all apps are running in the internal memory, not using the external memory card space. This may be unnecessary but is what I did to be safer should something go wrong. Use App 2 SD Free to copy all of your apps back to internal memory before beginning.

Next, use ES File Explorer or Astro (Free at the Market) to copy the contents of /mnt/sdcard to /mnt/sdcard/external Be sure NOT to copy the existing "external" directory when selecting the files/directories to copy.


Reboot the Vizio VTab to make sure nothing is running in the background.

This next part took me a bunch of tries to get the commands to take. If you get stuck, use ctrl-c to exit adb and try again. It may take quite a few times.

Now from a command prompt in Windows, execute these commands:

adb kill-server
adb shell
(You're now in adb)
su
(You now have the # superuser prompt)
mount -o rw,remount -t yaffs2 /dev/block/mmcblk0p2 /system
chmod 777 /system/etc (you can now delete and modify from /system/etc, so be careful)

DO NOT REBOOT YET. Rebooting appears to reset the file permissions.

Using Astro, make a copy of vold.fstab in case you wish to restore to stock behavior later.

Now this is where it gets a little odd. I had trouble editing vold.fstab and saving. So I deleted vold.fstab and then immediately copied the vold.fstab copy back into the directory. It's apparently a permission issue if someone wants to figure out what to send to enable editing without this delete/copy step.

Using Astro, edit /system/etc/vold.fstab Choose "as text" and then file editor"

Go down to the uncommented line for mounting sdcard and remove "/external"
Go to the next line for mounting internalstorage and change it to /mnt/sdcard/internal <--- NOTE: This is not working. Can someone figure out why and what to change?

(When a line has a # as the first character, it's a commented out line. So look for the lines without the # symbol as the 2 lines to modify.)

Reboot

If you want to verify you're now running off the memory card as the default SDCard, load "App 2 SD Free" from the market. Run it. Select "On SD Card" and the meter at the bottom will tell you how much space you have on the SD Card. With a 32 gig card, it tells me I have 29.56 available. Prior to this, I had around 1.8 gig, or whatever the stock amount was.

Now use App 2 SD Free to move your apps back to the SD Card.

Enjoy your big new SDCard space.

[rprr]

Go to the next line for mounting internalstorage and change it to /mnt/sdcard/internal <--- NOTE: This is not working. Can someone figure out why and what to change?
(

Great work. Would the following help (Using adb and as 'su')?

mkdir /mnt/sdcard/internal

The above creates the needed mount-point.

Have you rebooted a couple times to make sure that these changes persist?

[marvin02]

. . . .

Go to the next line for mounting internalstorage and change it to /mnt/sdcard/internal <--- NOTE: This is not working. Can someone figure out why and what to change?

. . . .

Did you create a folder named internal on the external sd card?

Did you try creating a folder named external on the external sd card and just switching the mount points?

I am waiting for all of the files to copy from my internal memory to the external card so I can do some tests.

[nb45cl]

No, I forgot to create the /mnt/sdcard/internal directory. That's probably the issue. I'll try it in the morning and see if that fixes the mounting isue.

It does persist between reboots as this is a change to the configuration files. It's just a swap of internal and external memory cards.

Now the next thing is whether someone can figure out how to increase the 800gb app partition. It's too small with a 32gb card. The Archos 101 only has 300gb availablle despite being a 16gb tablet. So I guess the Vizio is in good shape, in comparison.

[rprr]

Unfortunately, the /mnt/sdcard/internal trick did not work Therefore, as suggested, I swapped the internal and external partition mounts. The two lines in my vold.fstab are:

dev_mount sdcard /mnt/sdcard auto /devices/platform/sdhci-pxa.0/mmc_host/mmc1
dev_mount internalstorage /mnt/sdcard/external 4 /devices/platform/sdhci-pxa.2/mmc_host/mmc0

It is all good now