[Completed] Need info on the deeper levels of storage access: formatting, repartitioning, etc - XDA Assist

I think I have a decent grasp of how the Android system functions, what the partitions are, what's stored on each partition, etc.
However, I've recently been put in a strange situation with my Note 4, requiring me to do a repartition of the internal memory, basically wiping everything and starting from 0. I realised I have basically 0 info on this, except using a PIT file in ODIN, and even then the concept is a bit fuzzy.
I need to understand some things:
- where exactly is the software that allows a connection to ODIN stored? Is it in sort of a BIOS of the phone? Is there an equivalent to a BIOS on a smartphone?
- can the internal memory ever be fully wiped and repartitioned like you can do to a PC's HDD or SSD? If so, how exactly? What are the tools needed? What are the risks?
- I keep reading about soft bricked and hard bricked phones. How exactly does a phone become hard bricked?
- Could you recommend some literature or wikis, forum posts, etc. on this subject?
Thank you very much.

SCViper said:
I need to understand some things:
- where exactly is the software that allows a connection to ODIN stored? Is it in sort of a BIOS of the phone? Is there an equivalent to a BIOS on a smartphone?
Click to expand...
Click to collapse
I'm not really a Samsung man but the software used to connect to odin is download mode which I think is the SBL partition (secondary bootloader.) On LG devices it's called the laf partition. That would be the closest equivalent to a BIOS. I found this thread which takes a good look into the partitions of various phones: http://forum.xda-developers.com/showthread.php?t=1959445. (It says it's for the El Grande but it has info for galaxy's, LG's etc).
- can the internal memory ever be fully wiped and repartitioned like you can do to a PC's HDD or SSD? If so, how exactly? What are the tools needed? What are the risks?
Click to expand...
Click to collapse
You can re-partition the internal memory but not exactly like a PC. Some people do it to increase the size of the /data partition with space from /sdcard (internal memory.) For some devices you can use a simple linux utility like parted but for a samsung it's done by editing your pit file. Have a look at these 2 links.
http://forum.xda-developers.com/gal.../mod-partition-internal-memory-t-989-t3051556
http://forum.xda-developers.com/xperia-l/general/guide-repartition-internal-memory-data-t3052242
- I keep reading about soft bricked and hard bricked phones. How exactly does a phone become hard bricked?
Click to expand...
Click to collapse
I've never hardbricked a device, even after wiping my main partitions. It's just a general term for when your phone is so badly borked that it's completely unresponsive and you can't even access it by pc. Mostly by hardware failure.
- Could you recommend some literature or wikis, forum posts, etc. on this subject?
Click to expand...
Click to collapse
Check out the above threads and just have a look around here yourself for others. If you want to post a new topic it might be better to ask in your device section to get advice that's more relevant to your phone.

Thanks for this answer, I'll read the topics you've posted and see what's there.

Thank you very much Art, I've (finally) read the topics you posted and now have a better understanding of Android partitions.

Related

[Q] Can't change (any) memory contents on sns

Hi!
Some time lurker but it's my first post.
I just created this post because of the 10 posts rule on dev section.
Following this thread:
http://forum.xda-developers.com/showthread.php?t=947950
My problem is:
Phone boots right, after unlocking the screen the error messages start.
Any settings changed get lost after reboot.
Can't change anything, even SD card contents
What I tried:
I can install clockwork (it's the only partition I can change)
But nothing more. Because what ever I copy from pc to SD card get lost when unmounting from pc. Not even NAndroid
With fastboot only flashing recovery works.
With others I get errors, I guess because it can't write to memory.
So I tried ODIN even with 512 .pit. Got firmware from samfirmware.com and other places
(I tried many times with different sources).
All procedure with Odin says sucessfull but when rebooting I got the previous installation unchanged.
It looks like I have a real ROM memory (in the real definition of the word) and nothing can change it. (A real unbrickable phone for ever )
I suspected first from hardware problem but if the problem was that I couldn't write to any partition, not even recovery (it's a single chip on motherboard). And if I mess up with pit and only repartitionate, the phone restarts over and over to bootloader.
If I repeat the steps again with correct files in Odin, it sucessfully reboots to the unchanged installation again. Like it never writed anything. Even the sdcard is unchanged with lot of musics ans photos.
Any ideas?
Thanks in advance
Anyone?
Anyone?
Are there any tool to format / resize change flash memory on Nexus S?
Like there are tools for HDD.
Or go to specific hardware and JTAG?
If you point me any direction it could help a lot.
Its not a single chip from my understanding. The sdcard partition is a seperare chip from the bootloader/recovery. Sounds like it could be a hardware issue. I have never heard of this exact problem though, most commonly the sdcard partition becomes unmountable
Sent from my Nexus S 4G using xda premium
Chip
I believe it's only one chip.
check step 10 on here
w_w_w.ifixit.com/Teardown/Nexus-S-Teardown/4365/2
and it's equal to my own motherboard,
Besides, the SDcard mounted on Nexus S is only ~13G , the rest is partitioned to system, boot, ...
yeah, I'm screwed
Anyone?
I'm screwed.
Anyone know where can I find motherboard to replace it?
(ebay has a lot of digitizers, flexs, etc but not motherboards)
Or maybe one to sell.
Or maybe figured out how to change NAND chip
Contact Samsung. They should repair it. Just sucks because you will be without your phone for two to three weeks.
Sent from my Nexus S 4G using xda premium

[SOLVED] Completely format system data cache partitions[making all zeroes]

I know the obvious ans would be to use 4ext superwipe.
What I want is like re-writing those partitions with all memory locations set to zeroes. The 4ext full wipe only works like quick format in windows desktop.
Any ideas how to do it?
____________________
Solved. See post 17 for details.
pushpann said:
I know the obvious ans would be to use 4ext superwipe.
What I want is like re-writing those partitions with all memory locations set to zeroes. The 4ext full wipe only works like quick format in windows desktop.
Any ideas how to do it?
Click to expand...
Click to collapse
Had to search a bit, but found an article that explains how to do this. It links to 3 apps (havn't tested myself, just remember there's no going back), from the description the first one only works on SD card, the second one might (it does not mention which partitions it formats), and the last one seems to be removed.
I did not read the whole article, but I suggest you do that before doing anything.
Good luck.
pushpann said:
I know the obvious ans would be to use 4ext superwipe.
What I want is like re-writing those partitions with all memory locations set to zeroes. The 4ext full wipe only works like quick format in windows desktop.
Any ideas how to do it?
Click to expand...
Click to collapse
Hi,
A RUU will reset everything back to stock, and fix any partition issues.
Is that what you are after?
malybru said:
Hi,
A RUU will reset everything back to stock, and fix any partition issues.
Is that what you are after?
Click to expand...
Click to collapse
As he said, he wants it to be completely formatted, meaning no data can be recovered, which is like a hard full wipe - no way to restore.
RUU does format the data partition, but it only removes records of files, and the data itself is still available and possible to read (until new files will be written over it).
No! I dont want to get involved with RUU stuff.. I just want to completely wipe my phone.. Like complete formatting of the USB drives. All system and data partitions set to zeroes.
In simple words, if you do quick formating on pendrives, you can restore (some or all data before format, depends on what you've put on the drive after format ) using some Data Recovery tools.
What i believe is that recovery just wipes the memory addresses, without putting zeroes on all the memory locations. have been googling for this for almost a week, haven't got any clue yet!
pushpann said:
I know the obvious ans would be to use 4ext superwipe.
What I want is like re-writing those partitions with all memory locations set to zeroes. The 4ext full wipe only works like quick format in windows desktop.
Any ideas how to do it?
Click to expand...
Click to collapse
I would do it this way (this is something I came up with, and if it screws up anything, you are responsible) :
Write a script that reformat your nand rom and then dumps (creates) a huge file containing zeroes. Then reformat using 4ext and repartition.
I am curious, why exactly do you want to do this? The lack of results from Google would suggest that this is not something people would normally do.
JAM THAT THANKS BUTTON.
Happy to help.
I assume you're not going to use the phone after?
If you aren't going to use the phone after, one word. Sledgehammer.
If you are keeping the phone; create a file on the partition filled with rubbish (linux has a command for this). Make sure it fills the entire partition and then run mkfs.ext4 /dev/block/partition. Repeat a dozen times or create a script to do it for you.
It's easier than erasing the whole NAND disk and partitioning it. Mainly because you'll wipe the recovery partition and create an expensive paperweight. Which brings me back to sledgehammer.
Sent from my HTC
pushpann said:
No! I dont want to get involved with RUU stuff.. I just want to completely wipe my phone.. Like complete formatting of the USB drives. All system and data partitions set to zeroes.
In simple words, if you do quick formating on pendrives, you can restore (some or all data before format, depends on what you've put on the drive after format ) using some Data Recovery tools.
What i believe is that recovery just wipes the memory addresses, without putting zeroes on all the memory locations. have been googling for this for almost a week, haven't got any clue yet!
Click to expand...
Click to collapse
On my first commented I linked to an article which gives two ways to wipe your phone (set to zeroes and all). Here are the two apps:
https://play.google.com/store/apps/details?id=com.kovit.p.forevergone
https://play.google.com/store/apps/details?id=ch.ethz.infsyssec.sddroid
Try those to see if they format the Data partition.
Far_SighT said:
I would do it this way (this is something I came up with, and if it screws up anything, you are responsible) :
Write a script that reformat your nand rom and then dumps (creates) a huge file containing zeroes. Then reformat using 4ext and repartition.
I am curious, why exactly do you want to do this? The lack of results from Google would suggest that this is not something people would normally do.
JAM THAT THANKS BUTTON.
Happy to help.
Click to expand...
Click to collapse
Hmm.. My phone has become very laggy.. No matter what ROM flash, what firmware I flash.
DennisBold said:
I assume you're not going to use the phone after?
If you aren't going to use the phone after, one word. Sledgehammer.
If you are keeping the phone; create a file on the partition filled with rubbish (linux has a command for this). Make sure it fills the entire partition and then run mkfs.ext4 /dev/block/partition. Repeat a dozen times or create a script to do it for you.
It's easier than erasing the whole NAND disk and partitioning it. Mainly because you'll wipe the recovery partition and create an expensive paperweight. Which brings me back to sledgehammer.
Sent from my HTC
Click to expand...
Click to collapse
By hearing what you say, i kinda feel little scared to do these steps. Anyway thanks for the suggestion..
astar26 said:
On my first commented I linked to an article which gives two ways to wipe your phone (set to zeroes and all). Here are the two apps:
https://play.google.com/store/apps/details?id=com.kovit.p.forevergone
https://play.google.com/store/apps/details?id=ch.ethz.infsyssec.sddroid
Try those to see if they format the Data partition.
Click to expand...
Click to collapse
Those apps dont work.. By internal data they mean internal sdcard not system or data partition.
BTW just saw this app called lagfix. It says it will discard the unused blocks, but doesnot work on my phone.. Has anyone tried it? For me it's saying trim on system,data and cache not supported! DAMN
DennisBold said:
I assume you're not going to use the phone after?
If you aren't going to use the phone after, one word. Sledgehammer.
If you are keeping the phone; create a file on the partition filled with rubbish (linux has a command for this). Make sure it fills the entire partition and then run mkfs.ext4 /dev/block/partition. Repeat a dozen times or create a script to do it for you.
It's easier than erasing the whole NAND disk and partitioning it. Mainly because you'll wipe the recovery partition and create an expensive paperweight. Which brings me back to sledgehammer.
Sent from my HTC
Click to expand...
Click to collapse
Yeah, I had similar thoughts. I was going for repartition becasue then the whole of nandroid can be wiped in one go.
To clean the phone, sledgehammer / mowing the device with a car (or both, one after the other) are the best methods.
Here's one more idea. Create a pseudo nandroid backup with all of your nandroid partitions(/system /data /cache etc) filled with garbage/zeroes. Then restore that. And bam, the nandroid is hard formatted (after a quick format of course).
Like always, it's your phone. I am not responsible for anything that you do to it.
JAM THAT THANKS BUTTON.
Happy to Help.
pushpann said:
Hmm.. My phone has become very laggy.. No matter what ROM flash, what firmware I flash.
By hearing what you say, i kinda feel little scared to do these steps. Anyway thanks for the suggestion..
Those apps dont work.. By internal data they mean internal sdcard not system or data partition.
BTW just saw this app called lagfix. It says it will discard the unused blocks, but doesnot work on my phone.. Has anyone tried it? For me it's saying trim on system,data and cache not supported! DAMN
Click to expand...
Click to collapse
Tried it yesterday, it's meant for certain devices that did not use the TRIM command like they should (Many Nexus 7 tablets were slowed down by this issue), but it seems the Sensation does not need it (or at least our kernels do not support the command).
What seems as the only way to do so is to create many blank files and delete them (like many already said). you can create a large file and copy it a few times to the Data partition, which will fill it, and then delete it. using a normal file manager will work (or you can use "adb push" command to push the file a couple of times).
Far_SighT said:
Yeah, I had similar thoughts. I was going for repartition becasue then the whole of nandroid can be wiped in one go.
To clean the phone, sledgehammer / mowing the device with a car (or both, one after the other) are the best methods.
Here's one more idea. Create a pseudo nandroid backup with all of your nandroid partitions(/system /data /cache etc) filled with garbage/zeroes. Then restore that. And bam, the nandroid is hard formatted (after a quick format of course).
Like always, it's your phone. I am not responsible for anything that you do to it.
JAM THAT THANKS BUTTON.
Happy to Help.
Click to expand...
Click to collapse
You sure it does complete format while restoring nandroid? BTW i still am not sure how to fill system and data partitions with zeroes or garbage! Anyway thanks for the heads up
pushpann said:
You sure it does complete format while restoring nandroid? BTW i still am not sure how to fill system and data partitions with zeroes or garbage! Anyway thanks for the heads up
Click to expand...
Click to collapse
You shouldn't have to worry about formatting empty space. No one ever, except possibly computer forensics is going to want information from an empty phone. They have access to browsing history from Google, call records from your mobile provider and ban access details from your banks. They wouldn't need your phone. There are things that make it hard for the average person. Including mounting the NAND disk in a way that it can be opened like a normal disk drive, and then running the tools to restore data. If someone really wanted data it's possible but they will not go through all that for 500MB of bank details, porn or whatever people do with phones these days. If you're trying to hinder the police because you did something wrong, then you should just stop.
Theoretically it can be done through an android device but cross compiling tools to recover data is long and tedious to do. There is nothing so important that someone would spend hours creating tools for an Android device to restore data that may already be irrevocably gone. Not to mention the learning curve for new software. If you are worried, burn the device and buy something new. That is the general rule for sensitive data. Make sure it's gone before you move on.
It's safe to click "Format all partitions" and then erase your SD card and give your phone away.
If it helps, install Android on top. Choose something big. Most of your application data is stored on your SDCard FYI.
Lastly, if it's lag you are trying to fix. Go backwards with Android not forwards. JellyBean demands more than ICS and ICS demands more than GingerBread. Having the latest OS doesn't work for everyone. For example, Windows 8.1 doesn't work for me because there's no fastboot support without huge editing of system drivers. The same is true in Android. GingerBread stability may be more important than ICS or JB features, or JellyBean features may be more important. However don't expect lag free 4.2 or 4.3, our devices may work with it, but they were never intended to go above 4.1(Ville C2 updates stop there too I think) due to hardware limitations. Others may argue differently, but you should question the effort they're (including me) putting in with kernel and device tree upgrades. It's amazing work nonetheless but it basically shouldn't have to be done if the device were supported. Buy a new device if you want the latest and greatest. My Sensation has become a trophy for me to the amazing things you can do with one of HTCs first dual core phones. I don't expect it to work without some kinks and bugs or even fatal flaws but I still respect it for having running Sense 3.0 to 5.0 (yes I've tried it).
Sorry for the rant. I'm a little bit grumpy, but hope it helps explains why you can mostly erase and install a new version of android then throw the device away and be relatively safe.
There's probably going to be someone who reads all of this and thinks I'm crazy, to that guy or girl. Thanks for reading all of it!
Sent from my HTC
DennisBold said:
You shouldn't have to worry about formatting empty space. No one ever, except possibly computer forensics is going to want information from an empty phone. They have access to browsing history from Google, call records from your mobile provider and ban access details from your banks. They wouldn't need your phone. There are things that make it hard for the average person. Including mounting the NAND disk in a way that it can be opened like a normal disk drive, and then running the tools to restore data. If someone really wanted data it's possible but they will not go through all that for 500MB of bank details, porn or whatever people do with phones these days. If you're trying to hinder the police because you did something wrong, then you should just stop.
Theoretically it can be done through an android device but cross compiling tools to recover data is long and tedious to do. There is nothing so important that someone would spend hours creating tools for an Android device to restore data that may already be irrevocably gone. Not to mention the learning curve for new software. If you are worried, burn the device and buy something new. That is the general rule for sensitive data. Make sure it's gone before you move on.
It's safe to click "Format all partitions" and then erase your SD card and give your phone away.
If it helps, install Android on top. Choose something big. Most of your application data is stored on your SDCard FYI.
Lastly, if it's lag you are trying to fix. Go backwards with Android not forwards. JellyBean demands more than ICS and ICS demands more than GingerBread. Having the latest OS doesn't work for everyone. For example, Windows 8.1 doesn't work for me because there's no fastboot support without huge editing of system drivers. The same is true in Android. GingerBread stability may be more important than ICS or JB features, or JellyBean features may be more important. However don't expect lag free 4.2 or 4.3, our devices may work with it, but they were never intended to go above 4.1(Ville C2 updates stop there too I think) due to hardware limitations. Others may argue differently, but you should question the effort they're (including me) putting in with kernel and device tree upgrades. It's amazing work nonetheless but it basically shouldn't have to be done if the device were supported. Buy a new device if you want the latest and greatest. My Sensation has become a trophy for me to the amazing things you can do with one of HTCs first dual core phones. I don't expect it to work without some kinks and bugs or even fatal flaws but I still respect it for having running Sense 3.0 to 5.0 (yes I've tried it).
Sorry for the rant. I'm a little bit grumpy, but hope it helps explains why you can mostly erase and install a new version of android then throw the device away and be relatively safe.
There's probably going to be someone who reads all of this and thinks I'm crazy, to that guy or girl. Thanks for reading all of it!
Sent from my HTC
Click to expand...
Click to collapse
I dont wanna sell my phone and I know that my data isnt that valueable that anyone will try to read my data with hard efforts. My sensation used to perform awesome 2-3 months back, and now that I must have quick formatted my system and data partitions more than 1500 times, i think a full wipe may do some help for those nag n lag issues.
And about going back to GB? Man, Everyone feels GB is sad after using ICS/JB. If my phone doesnot stop lagging every second after I format these partitions, i think its time for a new phone!
Anyway thanks for such a detailed reply
pushpann said:
I dont wanna sell my phone and I know that my data isnt that valueable that anyone will try to read my data with hard efforts. My sensation used to perform awesome 2-3 months back, and now that I must have quick formatted my system and data partitions more than 1500 times, i think a full wipe may do some help for those nag n lag issues.
And about going back to GB? Man, Everyone feels GB is sad after using ICS/JB. If my phone doesnot stop lagging every second after I format these partitions, i think its time for a new phone!
Anyway thanks for such a detailed reply
Click to expand...
Click to collapse
The lag isn't from formatting. You can try ARHD ICS if you want. Or probably Sense 4+ with 4.1.2 but anything above that might not work out great.
Sent from my HTC
pushpann said:
I dont wanna sell my phone and I know that my data isnt that valueable that anyone will try to read my data with hard efforts. My sensation used to perform awesome 2-3 months back, and now that I must have quick formatted my system and data partitions more than 1500 times, i think a full wipe may do some help for those nag n lag issues.
And about going back to GB? Man, Everyone feels GB is sad after using ICS/JB. If my phone doesnot stop lagging every second after I format these partitions, i think its time for a new phone!
Anyway thanks for such a detailed reply
Click to expand...
Click to collapse
How old is your Sensation? I could well be that your nand is dying. In that case, repartition your phone and make /system and /data from parts seldom used (like /cache).
If you want data security, full encryption will keep noobs away.
Thanks for the replies guys!
Today i actually did the zeroing of the partitions with Nandroid method.. I download an app called dummy file creator and it created dummy files(files with zeroes all over it. after searching in internet it seemed legit method of fully zeroing out the memory locations) in data partition untill it ran out of memory. Then i copied those files to system partition too manually till it also became full(I had to do this manually because the app didnt support creating dummy files in system partition) and made nandroid of data and system separately then did almost a dozen time 4ext format and restoring the nandroid. Finally i formatted all the partitions and installed Codename Lungo ROM(CM10.1).
HELL YEAH! it feels FASTer. Not sure if its gonna last long.
pushpann said:
Thanks for the replies guys!
Today i actually did the zeroing of the partitions with Nandroid method.. I download an app called dummy file creator and it created dummy files(files with zeroes all over it. after searching in internet it seemed legit method of fully zeroing out the memory locations) in data partition untill it ran out of memory. Then i copied those files to system partition too manually till it also became full(I had to do this manually because the app didnt support creating dummy files in system partition) and made nandroid of data and system separately then did almost a dozen time 4ext format and restoring the nandroid. Finally i formatted all the partitions and installed Codename Lungo ROM(CM10.1).
HELL YEAH! it feels FASTer. Not sure if its gonna last long.
Click to expand...
Click to collapse
Just found something and wanted to add - for future reference - Android Tuner seems to be able to make the TRIM operation on all partitions on our sensation, in a much easier way.
pushpann said:
Thanks for the replies guys!
Today i actually did the zeroing of the partitions with Nandroid method.. I download an app called dummy file creator and it created dummy files(files with zeroes all over it. after searching in internet it seemed legit method of fully zeroing out the memory locations) in data partition untill it ran out of memory. Then i copied those files to system partition too manually till it also became full(I had to do this manually because the app didnt support creating dummy files in system partition) and made nandroid of data and system separately then did almost a dozen time 4ext format and restoring the nandroid. Finally i formatted all the partitions and installed Codename Lungo ROM(CM10.1).
HELL YEAH! it feels FASTer. Not sure if its gonna last long.
Click to expand...
Click to collapse
Can you guide me? i want to do that but i'm noob . how did you do that? pls help me
BSHD666 said:
Can you guide me? i want to do that but i'm noob . how did you do that? pls help me
Click to expand...
Click to collapse
hehe you found it:good:

Data Recovery

Gentlemen
I have found multiple threads covering the aspects of this scenario, but none with a clear conclusion. It might be there, but then i haven't found them.
Long story short, I have been asked to assist with doing data recovery on a Note 10.1 . There is no external SD card, and there is no backup. I´m looking for a small 8kb key file, which was lost during a data crash of another application.
So fare, the task of running a data recovery util on the filesystem (On Track or similar) have been impossible , due to the fact that the device is not rooted, and attatching it as a mass storage device dosent seem to be possible.
From what i found, it´s only possible to get mass storage to work, if the device is rooted, and even so, it will only be the SD card which is accessible
So my questions are:
Is it possible , in anyway to get access to the filesystem, so i can do a scan for lost data?
Has anybody else had luck with retrieving lost data on souch a device?
Thanks in advance
S3 but basics are the same .
http://forum.xda-developers.com/showthread.php?p=45672474
http://forum.xda-developers.com/showthread.php?t=1994705
JJEgan said:
S3 but basics are the same .
http://forum.xda-developers.com/showthread.php?p=45672474
http://forum.xda-developers.com/showthread.php?t=1994705
Click to expand...
Click to collapse
Brilliant. This information is so much better then what i found so fare. Thanks!

What would happpen if i zero-filled the entire storage?

I'm new to rooting and installing new roms on android systems, but i work making custom linux and windows systems and optimizing for over a decade.
So, my optimizing spirit is tingling to try everything, but this particular thing is just a question, i'm not intending to actually do it.
When using the terminal on TWRP, i've noted that i could fdisk the internal storage (/dev/mmcblk0) and that i could see all the partitions it had, like system, data, cache and so on.
TWRP and other tools only re-format those partitions with ext4 in order to wipe, so i used 'dd' in terminal to zerofill the ones i knew i could wipe and then formatted then in ext4 (with 'dd if=/dev/zero of=partition').
But i had a bigger question and i couldn't find answer nowhere: What would happen if i actually used dd to zero fill EVERYTHING, the entire /dev/mmcblk0, including the very partition table, every byte on it?
Would the device still enter fastboot mode? Would i still be able to connect it on the fastboot utility and flash a new recovery or do something?
Or, if after zero filling, still on the terminal, if i used fdisk to re-create the proper partitions and then formatted them, could i reboot, re-flash the recovery (once there would be the partition for it) and do an very-deep-clean install?
Not that i think that this has any utility, i just wonder if this would end up rendering the device totally useless, or if the fastboot mode is stored in an ROM chip, like a computer bios is.
Guilherme Franco said:
I'm new to rooting and installing new roms on android systems, but i work making custom linux and windows systems and optimizing for over a decade.
So, my optimizing spirit is tingling to try everything, but this particular thing is just a question, i'm not intending to actually do it.
When using the terminal on TWRP, i've noted that i could fdisk the internal storage (/dev/mmcblk0) and that i could see all the partitions it had, like system, data, cache and so on.
TWRP and other tools only re-format those partitions with ext4 in order to wipe, so i used 'dd' in terminal to zerofill the ones i knew i could wipe and then formatted then in ext4 (with 'dd if=/dev/zero of=partition').
But i had a bigger question and i couldn't find answer nowhere: What would happen if i actually used dd to zero fill EVERYTHING, the entire /dev/mmcblk0, including the very partition table, every byte on it?
Would the device still enter fastboot mode? Would i still be able to connect it on the fastboot utility and flash a new recovery or do something?
Or, if after zero filling, still on the terminal, if i used fdisk to re-create the proper partitions and then formatted them, could i reboot, re-flash the recovery (once there would be the partition for it) and do an very-deep-clean install?
Not that i think that this has any utility, i just wonder if this would end up rendering the device totally useless, or if the fastboot mode is stored in an ROM chip, like a computer bios is.
Click to expand...
Click to collapse
The hardware side of fastboot is typically stored on mmcblk0 somewhere in bootloader, meaning it is in the boot partition which is one of the things you would wipe. This would hardbrick your device, rendering it virtually unrecoverable, with a very slim chance of recovering, if its even possible at all, typically, it isn't possible.
Just stick with the tools already designed to handle any wiping that you need.
Sent from my SCH-I535 using Tapatalk
Droidriven said:
The hardware side of fastboot is typically stored on mmcblk0 somewhere in bootloader, meaning it is in the boot partition which is one of the things you would wipe. This would hardbrick your device, rendering it virtually unrecoverable, with a very slim chance of recovering, if its even possible at all, typically, it isn't possible.
Just stick with the tools already designed to handle any wiping that you need.
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That's interesting, i thought my fear was irrational, but it seems to be the case.
But, why is it like that? Why leave everything you need in an RW memory, while you could use a piece of ROM memory to grant the basic functions and the capability of manipulating the RW one (like a PC BIOS)?
In computers you usually don't need to mind wiping everything you can, your device will still work or will be at least recoverable.
Even screwing BIOS and firmwares in computers and some other devices is something that usually won't render the device unrecoverable. Although they sure can cause a hell lot of headache and may need physical intervention like soldering chips and such, i myself strove to find the correct bios images for certain motherboards and to flash the chips because i didn't have an proper flashing equipment, so i had to build an arduino circuit for that (but i luckily worked with detachable chips).
The only other device i know to be rendered unrecoverable are hard drives if you wipe the firmware stored in platter, as it has the service area, which keeps a big part of all information needed to properly address and read the disk and even the other system tracks spread through the disk, that are also needed to control the head, to read and to correct data errors.
Some of these are written at factory, but others must be writable so the hard drive can take care of itself.
But you'd only be able to mess with these data with proprietary low-level software using specific microcode, zero fill and low-level formatting software can't write on any of these tracks, they can only access LBA addressed tracks.
Guilherme Franco said:
That's interesting, i thought my fear was irrational, but it seems to be the case.
But, why is it like that? Why leave everything you need in an RW memory, while you could use a piece of ROM memory to grant the basic functions and the capability of manipulating the RW one (like a PC BIOS)?
In computers you usually don't need to mind wiping everything you can, your device will still work or will be at least recoverable.
Even screwing BIOS and firmwares in computers and some other devices is something that usually won't render the device unrecoverable. Although they sure can cause a hell lot of headache and may need physical intervention like soldering chips and such, i myself strove to find the correct bios images for certain motherboards and to flash the chips because i didn't have an proper flashing equipment, so i had to build an arduino circuit for that (but i luckily worked with detachable chips).
The only other device i know to be rendered unrecoverable are hard drives if you wipe the firmware stored in platter, as it has the service area, which keeps a big part of all information needed to properly address and read the disk and even the other system tracks spread through the disk, that are also needed to control the head, to read and to correct data errors.
Some of these are written at factory, but others must be writable so the hard drive can take care of itself.
But you'd only be able to mess with these data with proprietary low-level software using specific microcode, zero fill and low-level formatting software can't write on any of these tracks, they can only access LBA addressed tracks.
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Click to collapse
The simple answer would be that the manufacturers don't want you messing with the device to begin with so they don't do anything to make flashing or recovering easier for us.
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Galaxy On5 Data Recovery

Hi.
I mistakenly flashed my Android Galaxy On5 (using Odin's "AP" option) with one of the Exynos files. I saw something about "userdata" and knew immediately I had made a mistake, even though I did not load anything in the Odin "userdata" option. Why I did this probably isn't relevant, but I'm happy to provide more detail.
My question, however, is a simple one: Having done this, is it still possible to recover the user data that is no longer visible on the phone? When I reboot the phone without TWRP, it looks like it has been factory reset.
The phone is rooted, and I can see the device shares with "df". I can't see any secondary SD card based on the information I found about it sitting on top of where the SIM card is installed. I have done plenty of computer data recoveries from hard disk.. But every tool I have downloaded online for the Android seems to be polluted with malware, and I even reimaged my desktop because of all the crap I've tried.
Do you have a recommended tool for this that isn't some horrible marketing ploy? Minitool, Dr.Fone, FonePaw, and Kingoroot were all unsuccessful.
Also, if the data resides on an internal SD card, how is it formatted? I assume it is not a typical EXT or NTFS file system. Can you tell me which device I should be trying to recover from? It looks like /dev/block/mmcblk0p21.
If the internal storage is inaccessible, another thought I had was to do a block copy (with dd) onto a separate SD card, but I am unsure of whether this would provide a copy of the overwritten data, or would it actually reduce my chances of recovery.
The phone is a Samsung Galaxy On5 (SM-G550T).
Much of the data is non-critical, but some of it is unfortunately irreplaceable. Again, I'm really looking for a "yes" or "no" here, either data recovery is possible or not. And of course any suggestions on how to do it are greatly appreciated. The time it took to flash was almost instantaneous, but I also realize that flash drives are different from spinning drives in terms of how data is written and stored.
Thank you.
libertine5 said:
Hi.
I mistakenly flashed my Android Galaxy On5 (using Odin's "AP" option) with one of the Exynos files. I saw something about "userdata" and knew immediately I had made a mistake, even though I did not load anything in the Odin "userdata" option. Why I did this probably isn't relevant, but I'm happy to provide more detail.
My question, however, is a simple one: Having done this, is it still possible to recover the user data that is no longer visible on the phone? When I reboot the phone without TWRP, it looks like it has been factory reset.
The phone is rooted, and I can see the device shares with "df". I can't see any secondary SD card based on the information I found about it sitting on top of where the SIM card is installed. I have done plenty of computer data recoveries from hard disk.. But every tool I have downloaded online for the Android seems to be polluted with malware, and I even reimaged my desktop because of all the crap I've tried.
Do you have a recommended tool for this that isn't some horrible marketing ploy? Minitool, Dr.Fone, FonePaw, and Kingoroot were all unsuccessful.
Also, if the data resides on an internal SD card, how is it formatted? I assume it is not a typical EXT or NTFS file system. Can you tell me which device I should be trying to recover from? It looks like /dev/block/mmcblk0p21.
If the internal storage is inaccessible, another thought I had was to do a block copy (with dd) onto a separate SD card, but I am unsure of whether this would provide a copy of the overwritten data, or would it actually reduce my chances of recovery.
The phone is a Samsung Galaxy On5 (SM-G550T).
Much of the data is non-critical, but some of it is unfortunately irreplaceable. Again, I'm really looking for a "yes" or "no" here, either data recovery is possible or not. And of course any suggestions on how to do it are greatly appreciated. The time it took to flash was almost instantaneous, but I also realize that flash drives are different from spinning drives in terms of how data is written and stored.
Thank you.
Click to expand...
Click to collapse
If you haven't any advice on how to do it, just a simple "yes" or "no" as to whether a recovery is possible would be greatly appreciated. There must be a few forum readers out there who know the answer to that question. Anyone? Bueller?
libertine5 said:
If you haven't any advice on how to do it, just a simple "yes" or "no" as to whether a recovery is possible would be greatly appreciated. There must be a few forum readers out there who know the answer to that question. Anyone? Bueller?
Click to expand...
Click to collapse
If you wiped out userdata, that means all your data is gone. I know for computers, deleting data doesn't necessary delete the data, but rather makes the space unallocated, meaning new data can be written over it. Not 100% sure if they have something similar for Android. If you have google synced with your account, you can recover most of your data that way, otherwise you might be out of luck.

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