How to Overwrite the hosts file - Android Q&A, Help & Troubleshooting

Hi Guys,
im looking for a way to Overwrite the Hosts File on
system/etc/
There is anyway to push the file inside an APK to this directory.
Or write a raw directly in the hosts file without root a device.
Thanks in advance.

This only works with Root!
Use a terminal emulator like this one:
Link
then you type in the following:
Code:
su
cd /system/etc
cp "location of the host file you want to overwrite the original with" hosts

Questions or Problems Should Not Be Posted in the Development Forum
Please Post in the Correct Forums
Moving to Q&A

/system should be on a ro partition, so after becoming root you also have to enable rw on it
with the terminal given above, type
#mount -o remount,rw -t yaffs2 /dev/block/$YOURBLOCK /system
where $YOURBLOCK is the /dev/block association given by the kernel. To find it just give a
#mount | grep /system
and change the first command accordingly

Related

Something is wrong

I wanna install a custom ROm on my lg optimus one but something goes wrong. I installed z4root and rooted the phone. Then i installed terminal emulator and typed the specific code starting with su .The phone restarted and i pressed and kept pressing the 3 buttons (power+vol. down+home) but no menu apeared. I did the procedure 10 times but the menu didn't apeared. Am i doing something wrong or my pfone is brocken?
Did u copy paste all commands at once?
I did it manually tiping it by hang on my phone. I didn't coppy the text from my computer.
seems you didnt unzip the two recovery image files. Check it.
I unzipped all the files the image file, the recovery file, everithing. And i coppyedboth the zipped and the unzipped files
I checked it again and i have ony one recovery file and not 2... Which is the second recovery file?
Read this, I just instructed another user on how to upgrade to version 1.2 of the custom recovery. You should install it too. You will find links to the two files and the commands to type in the terminal.
Good luck!
flash_image.zip ??
I have flash_image zipped and unzipped
Use this: http://forum.xda-developers.com/showthread.php?t=971245
when i type the code it says:
$ su
# mount -o remount,rw -t yaffs2 /dev/block/mtdblock1 /system
# cat /sdcard/flash_image > /system/bin/flash_image
cannot create system/binflash_image: read-only file system
# chmod 755 /system/bin/flash_image
# mv /system/etc/install-recovery.sh /system/etc/install-recovery.sh.bak
# mount -o remount,ro -t yaffs2 /dev/block/mtdblock1 /system
# flash_image recovery /sdcard/LGp500-recovery-v12.img
# reboot recovery
Use what I told you and forget about those lines !
Try copy paste each command one by one....
I did just like here: http://forum.xda-developers.com/showthread.php?t=971245 but an error apeared: "windows cannot find groot.exe". I saw that there was anotxer member with the same problem but i didn't understood how to fix it.
try copy paste from stock browser on phone to terminal

[Q] Custom host file

Hi everyone,
I'm trying to put a custom hosts file on my TB to block ads, what I need to know is the syntax of the commands to remount the file system as rw. I've found this for another phone but I don't know if the command changes from phone to phone.
busybox mount -o remount,rw /system

Foreign Language Character Fonts - How To Add

Unfortunately Android does not yet support certain foreign language characters out-of-the-box. For example, I need to have Armenian character support.
I thought I would re-post the steps I've followed to add the necessary support.
1. You must obtain ROOT.
2. Download DejaVu fonts. (attached)
3. Extract the file DejaVuSans.ttf and save it as DroidSansFallback.ttf
4. Copy the file DroidSansFallback.ttf to the root directory of your SD card.
5. Enter the following terminal commands. I use adb shell, but there are other ways of course.
su
mount -o rw,remount -t yaffs2 /dev/block/mtdblock3 /system
chmod 4755 /system/fonts/DroidSansFallback.ttf
cp -rf /sdcard/fonts/DroidSansFallback.ttf /system/fonts/DroidSansFallback.ttf
reboot​
Note, the exact path of the sdcard may vary from device to device. Check the properties of the file from the device itself to confirm its exact location.
Hope this helps!

[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] Hosts file ressetting on reboot

Does anybody know why my hosts file gets reset after a reboot no matter whether I change with adaway or adblock or if I manually replace the hosts file myself and set to read only. Have searched about and only solution I read about was get a custom kernel. Although I am already on a custom kitkat ROM and using dorimanx kernel for galaxy s2. Also never had problems with hosts resetting on jb or ICS. Even creating a symlink to data/data/hosts doesn't work. On reboot the symlink just gets replaced with the original useless hosts file.
Sorry to bump but it is irritating and can't find a solution.
just some hints,
hosts file is located on /system partition which should be read only mounted during runtime.
check:
Code:
# mount | grep /system
/dev/block/mmcblk0p9 /system ext4 ro,seclabel,relatime,user_xattr,barrier=1,data=ordered 0 0
ro is ok. If so, the file can be changed only during boot (some init script) or later by app with root permission.
check if some init script is not involved:
Code:
# grep hosts /init*
Code:
#grep hosts /system/etc/init.d/*
Is there any output of the commands? I'm on i9100/CM10.2 and there is no output.
Then would be good to revoke root permissions to all apps (not unroot) and see if the issue is still there.
and also check the time of last change of the file:
Code:
ls -l /system/etc/hosts
is it realy during boot?
After spending entirely too much time on this I finally have a working solution. Save the contents of this script to your internal SD card. Ensure the last line is a blank carriage return.
Code:
#!/system/bin/sh
sleep 10
mount -o rw,remount /system
cp /storage/emulated/0/Download/working/hosts /system/etc
Install Script Manager (SManager), and set this script as: on boot, executable, as root. This will then copy your custom "hosts" file under your SDcard to /system/etc after 10 seconds.
Using this script through init.d didn't work for me, which I guess means whatever was over-writing my "hosts" file was doing after the init.d process.
Definitely remount system partition to read only again. Append following line to your script:
Code:
mount -o ro,remount /system
d0gd3v said:
Definitely remount system partition to read only again. Append following line to your script:
Code:
mount -o ro,remount /system
Click to expand...
Click to collapse
good call, thanks

Categories

Resources