[Q] How can I mount /system as writeable in adb shell? - Barnes & Noble Nook Tablet

I thought I'd bricked my NT but it would appear that it is actually alive because it turns up with adb and I can get shell and then issue command su, but what I can't do is replace the old build.prop because file system is not writable. How do I remount it to be writeable from a shell please?
Thanks!

CelticWebSolutions said:
I thought I'd bricked my NT but it would appear that it is actually alive because it turns up with adb and I can get shell and then issue command su, but what I can't do is replace the old build.prop because file system is not writable. How do I remount it to be writeable from a shell please?
Thanks!
Click to expand...
Click to collapse
mount -o rw,remount -t ext4 /dev/block/mmcblk0p8 /system
Type mount to verify rw, make your changes
mount -o ro,remount -t ext4 /dev/block/mmcblk0p8 /system
Type mount to verify ro

Thank you!

hwong96 said:
mount -o rw,remount -t ext4 /dev/block/mmcblk0p8 /system
Type mount to verify rw, make your changes .....
Click to expand...
Click to collapse
I don't have this tablet but a phone with similar problem.
this does not work for me, although I have ROOTED phone MTK6572, android 4.2.2 ;
"/ root" gets RW, but "/system" stays RO.
I get this message:
error
"the item "system" is read only"
I have tried many apps in phone (remount system RW, FX file expl. ....), and mtkdroid-tools and ADB shell in PC.
I have tried many similar version of that command, too, inc. busybox remount. non of those work.
any ideas, what to try next?
what file or thing or item and where I need to change to get this remounting system to RW done?
it is ext4, and remountable.
I have SuperSU in phone but can't update its binaries: /system stays RO, what ever I try...
I can't change audios, anything in /system.
very annoying...

Jack_Rover said:
I don't have this tablet but a phone with similar problem.
this does not work for me, although I have ROOTED phone MTK6572, android 4.2.2 ;
"/ root" gets RW, but "/system" stays RO.
I get this message:
error
"the item "system" is read only"
I have tried many apps in phone (remount system RW, FX file expl. ....), and mtkdroid-tools and ADB shell in PC.
I have tried many similar version of that command, too, inc. busybox remount. non of those work.
any ideas, what to try next?
what file or thing or item and where I need to change to get this remounting system to RW done?
it is ext4, and remountable.
I have SuperSU in phone but can't update its binaries: /system stays RO, what ever I try...
I can't change audios, anything in /system.
very annoying...
Click to expand...
Click to collapse
I understand your frustration, however, you should try to post your question to the MTK6572 or Samsung S4 thread. Anyway, since you have asked I'll answer. The mount point for /system is different on each phone model. There is no one standard /system mount point. On the Nook Tablet and Nook Color it is mmcblk0p8. On your device it is different, so the command you tried will not work.
You need to find out what the /system mount point is for your phone.
Open terminal from phone and type su.
Press enter.
At the # prompt type cat /proc/mtd
Press enter.
Look at the output on the screen and see what the mount point is for /system.
A the the # prompt type mount -o rw,remount -t ext4 /dev/block/enteryoursystemmountpointhere /system
Note: replace enteryourmountpointhere with your mount point from the previous step.
Change /system to ro when done. Hope this works for you.
Also download root checker app to ensure you rooted properly.

hwong96 said:
I understand your frustration, however, you should try to post your question to the MTK6572 or Samsung S4 thread. ......
Click to expand...
Click to collapse
thanks for your responce.
with that "cat ..." I got : "no such file or dir"...
I know already that my mnt point is (did try already these earlier):
mount -o rw,remount /dev/block/mmcblk0p4 system
mount -o remount,rw -t ext4 /[email protected] /system
but no success, " system read only" stays, and no change.

Jack_Rover said:
thanks for your responce.
with that "cat ..." I got : "no such file or dir"...
I know already that my mnt point is (did try already these earlier):
mount -o rw,remount /dev/block/mmcblk0p4 system
mount -o remount,rw -t ext4 /[email protected] /system
but no success, " system read only" stays, and no change.
Click to expand...
Click to collapse
Did you use the root checker app to verify for proper root?

hwong96 said:
Did you use the root checker app to verify for proper root?
Click to expand...
Click to collapse
yes.
I have many apps (e.g. FX, ATools, TitaniumBup, busybox, ES, mount /system rw, SD maid, root expl., adbd insec., rootAppDel, a.s.o.) that use root rights, and phone's superSU gives the rights to them.
AT:s terminal has # prompt, so it must be root. (?)
adbd insecure's current status = binary: insecure; usb debugging: enabled.
I have earlier version SU's binaries working ok, but updating SU made this binary-update-issue: " binary update failure" and so SU-app won't open (it closes after failing binary update), though otherwise it works ok (and worked earlier until I did let G-play to update it, silly me!).
somehow my /system has been "open" i.e. RW earlier, since busybox and superSU has been installed, but now it is "stuck" to that RO-status. "/" opens, but "/system" not.
MTK Droid Root & Tools v2.5.3 (from here xdadevs) gets root shell ok, but fails when trying to install SU, busybox a.s.o. ("read-only system") - and it "crashes".
maybe kernel related? or boot loader, or .... what?
-----
btw, my apologises, that I wrote this issue to this thread, but I found my "problem" here with the search, and after posting I realized that this is "tablet area..."
so this part can be moved to better place by those who know best where to - though not to trash, anyway....

Jack_Rover said:
yes.
I have many apps (e.g. FX, ATools, TitaniumBup, busybox, ES, mount /system rw, SD maid, root expl., adbd insec., rootAppDel, a.s.o.) that use root rights, and phone's superSU gives the rights to them.
AT:s terminal has # prompt, so it must be root. (?)
adbd insecure's current status = binary: insecure; usb debugging: enabled.
I have earlier version SU's binaries working ok, but updating SU made this binary-update-issue: " binary update failure" and so SU-app won't open (it closes after failing binary update), though otherwise it works ok (and worked earlier until I did let G-play to update it, silly me!).
somehow my /system has been "open" i.e. RW earlier, since busybox and superSU has been installed, but now it is "stuck" to that RO-status. "/" opens, but "/system" not.
MTK Droid Root & Tools v2.5.3 (from here xdadevs) gets root shell ok, but fails when trying to install SU, busybox a.s.o. ("read-only system") - and it "crashes".
maybe kernel related? or boot loader, or .... what?
-----
btw, my apologises, that I wrote this issue to this thread, but I found my "problem" here with the search, and after posting I realized that this is "tablet area..."
so this part can be moved to better place by those who know best where to - though not to trash, anyway....
Click to expand...
Click to collapse
Don't know what else to suggest, except maybe contact Chainfire on G+.

.

Related

[Q] How to get write access to system folder

I am trying to root an elocity A7 and I pretty new at this. I installed root explorer but the mount r/w button does not work in the system folder. I tried the terminal command below but it does not seem to accept the command. I get back a message that says shows Usage: mount [-r] [-w] [-o options [-t type] device directory. I retried root explorer and still can't write. Thanks for any help.
- open Terminal emulator:
$ su
# mount -o remount,rw /system
- open Root Explorer \system folder and press r/w
adb remount
or search the market for "mount system"
I'm not following how to use adb remount. What would be the complete command line? Also, I can't get to the market which is why I am trying this. I read it on another thread here.
i cant find mount r/w button
download this program from the market "Mount /system (rw / ro)"
I can't get to the market on this device. Any other way of getting it?
Try the attached zip
Thank you! That worked.
Code:
mount -o remount,rw -t yaffs2 /dev/block/mtdblock4 /system
Thanks For the App Recomendation
joenathane said:
download this program from the market "Mount /system (rw / ro)"
Click to expand...
Click to collapse
This was kicken my @$$ - thanks for the help and recommendation
zte with magisk
joenathane said:
Try the attached zip
Click to expand...
Click to collapse
my rom is stock but got a version that used zpst to force magisk to allow root, root is good but cant move 1 app to system without read only i tried this it says it worked but when i try to move it says i dont have permission .. guessing there isnt a recovery for this model the z835

[Q] Unable to change permissions or delete a specific file WITH root

Hello Gentlemen. Sorry to disturb you with a noob question but I cannot solve it for the life of me and I have tried everything I could find on the forums. I have an Aluratek Cinepad AT107F. I have successfully rooted it. I have full super user permissions and I have no problems deleting any files or folders EXCEPT one directory. Let me explain the situation.
I recently did a firmware update and it included brand new APKs for Youtube, also added Google Play Support, and added Angry Birds.
I am unable to update Youtube to the latest version. It gives a "Package file was not signed correctly. Uninstall the previous copy of the app and try again.".
So I attempted to do just what it had asked. I rooted just to do this. I tried removing it with Titanium Backup, I tried Root Uninstaller, I tried Root Explorer, I tried deleting using the "adb shell rm" command. I still get a "Read-only file system".
Even though I have root and granted root access to Root Explorer, I am unable to change the permissions for this /oem/apps/ directory. It's on the top level of the internal memory. I have no external SD card.
I've spent 10+ hours trying to figure this out and I'm sure someone knows something that I don't and can fix this super easy. I'm asking for your help, you're my only hope!
Your issue is that the update gave you modded files that the OEM doesn't want deleted. Most likely do to them not have permission from Google to do so. You will be hard pressed to find help here as we mainly deal with official releases and apks.
Wayne Tech S-III
zelendel said:
Your issue is that the update gave you modded files that the OEM doesn't want deleted. Most likely do to them not have permission from Google to do so. You will be hard pressed to find help here as we mainly deal with official releases and apks.
Wayne Tech S-III
Click to expand...
Click to collapse
Am I in the wrong sub forum? Is there another forum at XDA-Developers that could help?
Vindicoth said:
Am I in the wrong sub forum? Is there another forum at XDA-Developers that could help?
Click to expand...
Click to collapse
No nowhere on the site really deals with unofficial android versions and knock of devices. Your best bet will be the OEM
Read the error message again. The file is on a read-only filesystem. That is why you cannot delete it. In other words, you lack permission to write to the partition.
System partitions get mounted readonly to prevent modification. To remount /system as read-write,
Adb shell mount -o remount,rw /system
If you get "not permitted" error, your ROM's ro.secure means you cannot execute mount operations passed with adb command. So instead you must first open the shell,
> AdB shell
# mount -o remount,rw /system
Now you can delete:
Adb shell rm /system/file
If it is a directory
Adb shell rm -rf /system/dir
If you accidentally mistype that last command with a space beyween that first forward-slash and "s" you will have a very unworkable device....and that's why it is mounted read-only.
If the file is on a different read only filesystem, identify the partition the file is on and
Adb shell mount -o remount,rw /dev/block/id /LocToMountTo
You may have to specify the type
-t fstype
Adb shell mount
will tell you this
Don't forget to remount it as read-only (ro) when you are done
anotherguy19 said:
Read the error message again. The file is on a read-only filesystem. That is why you cannot delete it. In other words, you lack permission to write to the partition.
System partitions get mounted readonly to prevent modification. To remount /system as read-write,
Adb shell mount -o remount,rw /system
Now you can delete:
Adb shell rm /system/file
If it is a dir
Adb shell rm -rf /system/file
If you accidentally mistype that last command with a space beyween that first forward-slash and "s" you will have a very unworkable device....and that's why it is mounted read-only.
If the file is on a different read only filesystem, identify the partition the file is on and
Adb shell mount -o remount,rw /partition/id /folder
You may have to specify the type
-t fstype
Adb shell mount
will tell you this
Don't forget to remount it as read-only (ro) when you are done
Click to expand...
Click to collapse
Well I can access /system just fine. The problem is the /oem/apps folder is not in the /system folder. It's in the top level folder.
/system and /oem/apps are in the root directory. I can change the permissions on /system just fine using Root Explorer, but when trying to change the permissions using any method possible, /oem wont change.
This happens alot on Devices out of China and other places that sell knock offs. They make it so you cant delete their apps and if you do then it bootloops which only a reflash will fix.
Vindicoth said:
Well I can access /system just fine. The problem is the /oem/apps folder is not in the /system folder. It's in the top level folder.
/system and /oem/apps are in the root directory. I can change the permissions on /system just fine using Root Explorer, but when trying to change the permissions using any method possible, /oem wont change.
Click to expand...
Click to collapse
/system and /oem are different partitions then
mount | grep oem
or
adb shell mount | grep oem
Will tell you what /dev/block/xxxx the /oem is on and if it is mounted as read-only (ro)
> adb shell
# mount -o rw,remount /oem
zelendel said:
This happens alot on Devices out of China and other places that sell knock offs. They make it so you cant delete their apps and if you do then it bootloops which only a reflash will fix.
Click to expand...
Click to collapse
Ever get the feeling that you're writing in invisible ink lol?.. Eventually he will listen! You have great patience!
zelendel said:
This happens alot on Devices out of China and other places that sell knock offs. They make it so you cant delete their apps and if you do then it bootloops which only a reflash will fix.
Click to expand...
Click to collapse
Referencing zelendel's post, the device could fail to boot because it is looking for the removed app in /oem
So you could try to remove it from being referenced by the startup scripts.
Try doing a search for files that could be referencing the apk you want to remove.
> adb shell
# grep -r AppName.apk /system/etc
CtrlAltDelIrl said:
Ever get the feeling that you're writing in invisible ink lol?.. Eventually he will listen! You have great patience!
Click to expand...
Click to collapse
If it bootloops then I'll just flash it again, but its worth a try isn't it? Thanks anyways.
anotherguy19 said:
Referencing zelendel's post, the device could fail to boot because it is looking for the removed app in /oem
So you could try to remove it from being referenced by the startup scripts.
Try doing a search for files that could be referencing the apk you want to remove.
> adb shell
# grep -r AppName.apk /system/etc
Click to expand...
Click to collapse
Thank you for your very helpful posts and willingness to help me possibly bootloop my device
when I type the grep command it says it is not found, so I will download busybox onto my tablet and try those commands.
Vindicoth said:
Thank you for your very helpful posts and willingness to help me possibly bootloop my device
when I type the grep command it says it is not found, so I will download busybox onto my tablet and try those commands.
Click to expand...
Click to collapse
So after running mount | grep oem it shows this
[email protected]:/ # mount | grep oem
/dev/block/nandi /oem cramfs ro,relatime 0 0
So is it possible to change this directory to rw? I tried the mount -o rw,remount oem but it doesnt show anything after i input the command
[EDIT]
So it seems that the cramfs file system is read-only.
Vindicoth said:
Thank you for your very helpful posts and willingness to help me possibly bootloop my device
when I type the grep command it says it is not found, so I will download busybox onto my tablet and try those commands.
Click to expand...
Click to collapse
I love breaking things. It's only then we can figure out how it works.
Busybox is exactly what you need.
grep will search for strings within all files and subdirs of /system/etc; matching whatever you type for "AppName.apk"
It is a case-sensitive search unless you add
-i
So
grep -ri ....
or
grep -r -i....
Both would work.
But you don't even know if you need to be searching for a file to modify.
You may want to go ahead and delete the file and reboot.
If it fails, note the file(s) you deleted and know the system is looking for them and then proceed with seeing if you can identify a file in /system/etc that is looking for it's presence.
---------- Post added at 11:59 PM ---------- Previous post was at 11:53 PM ----------
Vindicoth said:
So after running mount | grep oem it shows this
[email protected]:/ # mount | grep oem
/dev/block/nandi /oem cramfs ro,relatime 0 0
So is it possible to change this directory to rw? I tried the mount -o rw,remount oem but it doesnt show anything after i input the command
[EDIT]
So it seems that the cramfs file system is read-only.
Click to expand...
Click to collapse
Commands that complete "quietly" mean they were successful.
If you type
# mount | grep oem
After
# mount -o rw,remount /oem
/dev/block/nandi /oem cramfs ro,relatime 0 0
Should have changed to
/dev/block/nandi /oem cramfs rw,relatime 0 0
anotherguy19 said:
I love breaking things. It's only then we can figure out how it works.
Busybox is exactly what you need.
grep will search for strings within all files and subdirs of /system/etc; matching whatever you type for "AppName.apk"
It is a case-sensitive search unless you add
-i
So
grep -ri ....
or
grep -r -i....
Both would work.
But you don't even know if you need to be searching for a file to modify.
You may want to go ahead and delete the file and reboot.
If it fails, note the file(s) you deleted and know the system is looking for them and then proceed with seeing if you can identify a file in /system/etc that is looking for it's presence.
---------- Post added at 11:59 PM ---------- Previous post was at 11:53 PM ----------
Commands that complete "quietly" mean they were successful.
If you type
# mount | grep oem
After
# mount -o rw,remount /oem
/dev/block/nandi /oem cramfs ro,relatime 0 0
Should have changed to
/dev/block/nandi /oem cramfs rw,relatime 0 0
Click to expand...
Click to collapse
Followed those steps and its still
/dev/block/nandi /oem cramfs ro,relatime 0 0
Apparently the cramfs is a read only filesystem by design.
Vindicoth said:
Followed those steps and its still
/dev/block/nandi /oem cramfs ro,relatime 0 0
Apparently the cramfs is a read only filesystem by design.
Click to expand...
Click to collapse
You need to create an image of the partition, mount the partition on a system with tools to edit it, extract the contents, and re-create the cramfs.
You would need a linux box or linux virtual machine like Virtualbox, or maybe cygwin has the tools. I would just download and burn a Linux LiveISO and run it from VirtualBox, creating a shared folder to get access to the image file (oem partition).
With debian system, you would do
# apt-get install cramfsprogs fusecram
fusecram allow you to mount the cramfs partition on Linux PC via
# mount -t loop cramfsOEM.partition /mnt/workingdir
However since we cannot simply mount the filesystem on the device by plugging into the usb port of the linux machine and mounting from there, we must first create an image (file) of /dev/block/nandi.
> adb shell
# dd if=/dev/block/nandi of=/nandi.img bs=4k
And then copy it to our pc so we can work with the file.
# exit
> adb pull /nandi.orig.img .
Now we can transfer this file to a machine with the requisite cramfs tools to modify the file.
If you look back, I wrote
# mount -t loop cramfsOEM.partition /mnt/workingdir
replace cramfsOEM.partition for nandi.orig.img, or whatever you named it.
Workingdir needs to exist, so
# mkdir /mnt/workingdir
Now you will have to look up cramfsprogs which will allow you to extract the contents to modify. On the Debian or Ubuntu linux machine "/mnt/workingdir" would be the equivalent of "/oem" on your Android device.
However, all this is could very well be for naught, as it is likely the firmware has marked this partition as "signed" so if we try to write back our modified image, the system will fail to boot since the size will be different. On the other hand, the firmware may very well just check to see the partition size is correct. And since you are decreasing the size, the new cramfs image created with a linux box will (should) fit in the old partition.
Fyi, an image file is like a zip file without the compression.
After you modify the cramfs, you can write it back with something like
> adb push cramfs.mod.img /
> adb shell
Then write over the old partition. However, you shouldn't write over a mounted file system so
# umount /dev/block/nandi
Then write over it.
# dd if=/cramfs.mod.img of=/dev/block/nandi bs=4k
Then reboot
# shutdown -r now
And see what happens.
anotherguy19 said:
You need to create an image of the partition, mount the partition on a system with tools to edit it, extract the contents, and re-create the cramfs.
You would need a linux box or linux virtual machine like Virtualbox, or maybe cygwin has the tools. I would just download and burn a Linux LiveISO and run it from VirtualBox, creating a shared folder to get access to the image file (oem partition).
With debian system, you would do
# apt-get install cramfsprogs fusecram
fusecram allow you to mount the cramfs partition on Linux PC via
# mount -t loop cramfsOEM.partition /mnt/workingdir
However since we cannot simply mount the filesystem on the device by plugging into the usb port of the linux machine and mounting from there, we must first create an image (file) of /dev/block/nandi.
> adb shell
# dd if=/dev/block/nandi of=/nandi.img bs=4k
And then copy it to our pc so we can work with the file.
# exit
> adb pull /nandi.orig.img .
Now we can transfer this file to a machine with the requisite cramfs tools to modify the file.
If you look back, I wrote
# mount -t loop cramfsOEM.partition /mnt/workingdir
replace cramfsOEM.partition for nandi.orig.img, or whatever you named it.
Workingdir needs to exist, so
# mkdir /mnt/workingdir
Now you will have to look up cramfsprogs which will allow you to extract the contents to modify. On the Debian or Ubuntu linux machine "/mnt/workingdir" would be the equivalent of "/oem" on your Android device.
However, all this is could very well be for naught, as it is likely the firmware has marked this partition as "signed" so if we try to write back our modified image, the system will fail to boot since the size will be different. On the other hand, the firmware may very well just check to see the partition size is correct. And since you are decreasing the size, the new cramfs image created with a linux box will (should) fit in the old partition.
Fyi, an image file is like a zip file without the compression.
After you modify the cramfs, you can write it back with something like
> adb push cramfs.mod.img /
> adb shell
Then write over the old partition. However, you shouldn't write over a mounted file system so
# umount /dev/block/nandi
Then write over it.
# dd if=/cramfs.mod.img of=/dev/block/nandi bs=4k
Then reboot
# shutdown -r now
And see what happens.
Click to expand...
Click to collapse
Wow that was very detailed. I thought I might have to do something like that. Thanks so much again. I'll try this in the morning since it's getting very late here. I'll go ahead and download a linux livecd tonight.

[Q] No root access in ADB shell?

Hi! I'm having a few problems with my Galaxy Nexus, as it's been not booting with this CyanogenMod 11S bootanimation.zip I've been trying. I now want to remove it, but I can't boot into recovery due to hardware issues. I can adb into the phone though, but only shortly, before the system locks up.
I'm trying to do the following:
Code:
su
mount -o remount,rw -t ext4 /dev/block/mmcblk0p1 /system
cp /sdcard/bootanimation.zip /system/media/bootanimation.zip
However, I can't use "su" - nothing really happens. It won't give me root, but it doesn't give any errors either, the $ sign doesn't change into a # sign, thus remounting system to rw fails and subsequently, I can't copy anything there.
I'm running PACman (4.4.2) and I have SuperSU installed. Any ideas?
Edit - Kind of solved, forgot adb reboot recovery existed.

[Q] Error while Rooting - /System Read-Only filesystem

Hey there guys.
I have a couple of devices I am trying to root.
One is a ZTE Fit 4G and the other is a cheap tablet bought from ebay with an allwinner A20 marked as MIB in about.
I have tried many ways of rooting on both of them. One of which was Cydia Impactor.
I have used Cydia Impactor to root other devices just fine.
However on these 2 devices when i run "# drop SuperSU su to /system/xbin/su" the payload runs on the device and then Cydia Impactor shows "mount: Read-Only filesystem"
When i try adb remount I get remount failed: Read-only file system
Also when i try this in adb shell - mount -o rw,remount /system I get the same error mount: Read-only file system
Of course I get the same message with mount -o remount,rw /dev/block/mtdblock3 /system
All these commands are done while the phone is running. should i be in recovery mode or something while I do this?
If that is not the case then how would I go about making the file system writable or is there away to root the device without modifying system and once rooted install supersu and binaries manually (I am assuming the only access to /system is to install super su... which could be totally wrong)
I appreciate your time in reading this and look forward to hearing any suggestions you may have,
Kriogenic.

how to mount modem partition as r/w?

my modem partition shows as protected in flashfire.im guessing its read only? how would i mount it as r/w in adb.I have root and busybox. the mmc block is /dev/block/mmcblk0p1
adb shell
su
# # mount -o remount,rw /dev/block/mmcblk0p1?
i've tried that command, i dont know if its correct it give no errors but its still read only
Sorry
But have you found a way to mount modem partition
What is the command for it?
I accidentally erased all by flash tool
And now SIM not working
Even after flashing stock rom
I have Lenovo phab plus
And I could only install twrp recovery and root
But the recovery can't mount
It returns to default again after restart
jass65 said:
my modem partition shows as protected in flashfire.im guessing its read only? how would i mount it as r/w in adb.I have root and busybox. the mmc block is /dev/block/mmcblk0p1
adb shell
su
# # mount -o remount,rw /dev/block/mmcblk0p1?
i've tried that command, i dont know if its correct it give no errors but its still read only
Click to expand...
Click to collapse
You need insecure ADB to do that, which requires ROM modification. Or do it in TWRP, which is insecure by default.
Insecure ADB is enabled by "adb root" on your PC.
Also, when remounting, you should specify the mount point - not the block device. E.g. /modem. You can check "mount" command to find the existing mount point.
Boot into TWRP and run:
adb shell mount -o rw,remount /modem or /firmware
But you may get errors as this partition is probably write-protected. You'd need to modify your fstab to make it always read-writeable
The best way to modify is to dump the partition and modify within Linux then reflash to the device

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