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Help I unrooted my Samsung Tab 4 8", but "Software Update' still says "OS is modified"

C

cutedroid

Well-Known Member
I have a Samsung Tab 4 8-inch, wifi-only tablet (Model number: SM-T330NU)
.
Several months ago, I rooted it with Towelroot several months ago. Today, I tried to run Software Update (in Settings/General/About_Device), but it says,

"The operating system on your device has been modified in an unauthorized way. Try downloading software updates using Samsung Kies on your PC, or visit a customer service center."​

So I tried to unroot the phone. I opened SuperSU app (by Chainfire). When it asked me if I wanted to disable Kies, I chose "No" (advised by http://gs5.wonderhowto.com/how-to/unroot-your-galaxy-s5-other-android-device-0156117/). I went to Settings, and then I scrolled all the way down till I got to "Full Unroot". I then tapped that. I then rebooted.

With the Root Checker app, I verified that I was indeed unrooted.


I then tried to run Software Update again, but I still got the same message. What's wrong?
 
glc said:
You made changes to the operating system.
Why else would you root?
Click to expand...
GLC, thank you for your reply. Let me re-cast your words, as I understand you:

Rooting your phone produced changes in the operating system.​

I'm still left with the question, "If unrooting does not undo all the changes in the operating system, what else must I do (or "undo")?
 
Probably everything you did to the system while rooted.
That is likely impossible, so you need to reinstall the original software.
 
Yeh, you need to re-install the original Samsung ROM, even though you removed the root, there's something in system that's still in a modified state, maybe a file or something. I believe it runs a checksum hash of the current system on the device, and if that checksum hash doesn't match the hash expected by the update, it's "modified". They do this to try and ensure that incremental OTA updates are successful, because if something is not as Samsung intended in the current firmware, it may well fail resulting in a malfunction, e.g. things keep crashing, a boot-loop or very possibly a completely bricked device.
 
Last edited:
Thank you, glc and mikedt, for your replies. I'm willing to reinstall the original software, butw here can I get the original Samsung ROM? I tried Google.
 
mikedt said:
Here, look for your particular Samsung by model number and/or device type.
http://www.sammobile.com/firmwares/
Click to expand...
Mike, thank you for the link. I found the page for my Tab 4 8inch: http://www.sammobile.com/firmwares/database/SM-T330NU/.

It's interesting that it has version 5.1.1. I assume that refers to Android version.
Question 1: Does this mean I can just install this 5.1.1 firmware?

The last column in the table is "Kies".
Question 2: Why is the Kies logo "whitened out" for the bottom 3 firmwares?

Question 3: How can I figure out what my Tab's PDA (4th column) and CSC (5th column) are?

Thank you. I feel like we're making progress. :)
 
Answer 1: the model numbers match up and both the Canadian and cellular south versions have 5.1.1 so yes actually, if you would like to you could update to Android Lollipop 5.1.1 if you flash that firmware.
Answer 2: I'm actually not so sure on that, maybe someone else can clear that up.... However if you use odin that shouldn't mean anything.
Answer 3:
d0d8d8a355e417ffb58abca16c88edf5.jpg

http://forum.xda-developers.com/galaxy-s3/help/guide-odin-flash-guide-t1671969

Sorry I got lazy and just posted a picture of the specific part that pertains to what pda and csc stand for instead of writing them out.
EDIT: I didn't actually answer your question, the pda and csc are usually your firmware version under settings>device info. It doesn't matter what it is now, as it will get overwritten and updated when you flash firmware.
 
Thank you, Blu8, for your response.
GLC & mike & all others, could you please let me me know whether it's safe to install the Lollipop ROM on my device?
 
Yes it should be. You're absolutely sure that's your model number and one of the two barrier versions is your carrier? If so then yes that lollipop update is for your device and it should be safe.
 
Hello, blu8. Well, I'm kinda nervous, because I'm not sure what the PDA and CSC of my Tab 4 are.
On my Settings/General/About_Device, I see the following:

Model Number
SM-T330NU

Android version
4.4.2

Kernel version
3.4.0-1337409
dpi@SWDD5901 #1
Mon Apr 21 12:33:36 KST 2014

Build number
KOT49H.T330NUUEU1AND4

SE for Android status
Enforcing
SEPF_SM-T330NU_4.4.2_0011
Mon Apr 21 12:33:09 2014

​
On the SamMobile page , the PDA and CSC end in BOG1, ANK1, and AND4. How can I find my PDA and CSC?
 
Blu8 said:
Yes it should be. You're absolutely sure that's your model number and one of the two barrier versions is your carrier? If so then yes that lollipop update is for your device and it should be safe.
Click to expand...
"Barrier version"? What do you mean?
 
Stupid keyboard, sorry I meant carrier. And they're not going to be the same, if you flash the same pda you're going to flash the version that you're on now. They don't have to match, in fact since you're going to update to a different version they shouldn't match. Did you find the firmware with the correct model number and carrier version? (Canada something or cellular south) if so that's all you need.
 
Blu8, thank you for your clarification. Well, I'm in Canada, and the Tab is from Canada. The tab is a wifi-only device; it has no cell phone apparatus, so I'm assuming that "Cellular South" is not what I want.

Please bear with me as I ask some more precautionary questions:
1.If I move from my current Android 4.2.2 to the 5.1.1 that is available on SamMobile, does this mean that all changes I've made on my Tab (for example, deleting a bloatware/system app while rooted) will be undone? In other words, is moving to 5.1.1 like getting this Tab brand-new from a store with 5.1.1 installed?

Or, to be verbose (but for the sake of communicating clearly), a factory reset on my Tab (see my OP) did not reset everything (as glc and mike) pointed out. They pointed out that a factory reset still left some changes I made (while I was rooted, I guess). Moving to 5.1.1 will completely remove all the "rooted" changes I did, yes?

2. If, while the Tab is trying to upgrade to 5.1.1, my Tab says "You are installing an incompatible firmware", does this mean that I've turned my Tab to a brick? In other words, will my Tab be smart enough to prevent an incompatible firmware from being installed? Or is there a chance I could brick my tab?

3. Related to No. 2, how can we be sure that the firmware on SamMobile is really official Samsung firmware?

4. Mikedt mentioned Samsung ROM. "ROM" and "firmware" mean the same thing, right?
 
Yes, flash that and its like a brand new just bought tablet that came with android 5.1.1. It will undo all of those changes.
Unfortunately no it will not warn you, but that is the correct firmware.
 
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