Why do people need write protection disabled when they boot into system?

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Cozume

Senior Member
Jan 30, 2014
429
97
From all I am reading, Android disables write protection when you boot into recovery and any changes that you make in recovery stick when you boot into system. And if you have root access, you can make changes to system in recovery.

So what advantages are there to having write protection disabled when you boot into system? Why can't you make any changes you want while in recovery? Isn't that safer anyhow? Do some apps need write protection disabled to run?
 

_Boondock_

Member
Apr 28, 2011
26
4
From all I am reading, Android disables write protection when you boot into recovery and any changes that you make in recovery stick when you boot into system. And if you have root access, you can make changes to system in recovery.

So what advantages are there to having write protection disabled when you boot into system? Why can't you make any changes you want while in recovery? Isn't that safer anyhow? Do some apps need write protection disabled to run?

I don't have a technical response or even very good response, but I do have an example of why you need access to the write protection.

I use AdAway to block advertising on my phone. (The ethics of doing this are up for debate, but lets leave that to another venue)
AdAway needs root access and the ability to modify the hosts file on the phone, which is a system protected file (for good reason). If write protection is on, then AdAway fails to modify the phone's hosts file and the ad blocking does not take place. With write protection off, AdAway is successful an my browser screen is far less cluttered when surfing.
I set the app to notify me when updates are available, but not to automatically apply the updates. Then I manually reboot to recovery and update my hosts file via AdAway. After I get the successful update I reboot normally and use my phone in the regular non-recovery mode.
 

Cozume

Senior Member
Jan 30, 2014
429
97
I use AdAway to block advertising on my phone. (The ethics of doing this are up for debate, but lets leave that to another venue)
AdAway needs root access and the ability to modify the hosts file on the phone, which is a system protected file (for good reason). If write protection is on, then AdAway fails to modify the phone's hosts file and the ad blocking does not take place. With write protection off, AdAway is successful an my browser screen is far less cluttered when surfing.

I set the app to notify me when updates are available, but not to automatically apply the updates. Then I manually reboot to recovery and update my hosts file via AdAway. After I get the successful update I reboot normally and use my phone in the regular non-recovery mode.
Ok, but that is my point - you can do it in recovery and in fact it is safer to do it in recovery. Stock android disables write protection when you boot into recovery.
 

Cozume

Senior Member
Jan 30, 2014
429
97
So we don't have to boot into recovery everytime we modify system.
Right, for convenience sake. But what I am asking is it ever necessary to have write protection disabled when you boot into system? Meaning, is there anything that you would need it for that booting into recovery to make the changes wouldn't work?
 

cartmenicus

Senior Member
Nov 27, 2011
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Right, for convenience sake. But what I am asking is it ever necessary to have write protection disabled when you boot into system? Meaning, is there anything that you would need it for that booting into recovery to make the changes wouldn't work?

You can't make changes to the system part I on with out write protection being disabled. Jcases method is a hacked recovery that when selected from fastboot boots you into a disabled system and you make your changes then reboot normally.

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