When I first got my G-tab I was baffled by all the instructions and the literally thousands of posts in the forum. Even now, I haven't been able to find exactly how (or why) I should update my kernel. That said, I have TNT Lite running and I love my g-tab. Exploring the possible uses and utilities on it provides hours of fun. Now - here is my question. I stumbled on some instructions for installing the ROM and I have used those same instructions to install several patches to the Rom. I see all this commentary on Clockwork, side loading, etc. and I wonder if I am missing something. Today I just installed the .25 patch for TNT-Lite. I downloaded the rar file, unzipped it on my PC to get the Recovery folder and the update.zip file. I plugged the g-tab into the pc and switched it to usb mode. Then I moved the old recover folder and update.zip to a folder (cautious me) and put the new ones in the root. I disconnected the usb and started the g-tab in recovery mode (holding the power and volume+ key. It rebooted, applied the patch and I was done. That seems simple enough. It would seem that this would work for switching roms, applying patches and probably even upgrading the kernel (If I knew where it was and why I should do it). Am I missing something? Everything seems to work.
Sounds like you got the basics ok.
The real main reason to update the kernal as i see it is to add things like driver support for devices like gps and g3, so on, also minor fixs. If your not using your gtab for anything like this you maybe happy to stay stock. But if you like myself like to use your gtab to surf with g3 or as a sweet gps, then thats what the kernal updates allow. Im sure others can correct me if ive got anything wrong or add to what ive said.
You got the basic steps right, but installing ClockWorkMod Recovery has a lot of benefits.
First, built in backup and recovery will save your skin if the gTab get "cranky".
Second, installing ROMs and/or updates saves you a few steps. From "tar" files (TnT-lite), extract the update.zip file to a folder (I created a folder named "xda", just an example) and name it after the version of ROM/update.
CWM will flash "*.zip" file. This way you can keep multiple ROMs/updates on the card and switch between them.
CWM lets you clear cache, wipe Data partition, clear Dalvik-cache (use caution there), fix permissions and so much more! It is a great tool.
Sent from my gTablet-TnT-Lite-4.2.5 using TapatalkPro
So now we peel back another layer
OK so now the question of multiple roms comes up. I am not clear about the role of the rom - can I switch roms and keep all of my apps and data intact? I'm thinking like changing style sheets on a web page - presentation is different but the underlying data is still the same? Is it that easy?
And... if I am doing that perhaps I need to "clear cache" or "wipe data partition" but although I like to investigate new things I'm not willing to just walk up and push the big red button without knowing what it is for. So why would I "clear" or "wipe" things?
I get the impression that I could switch between ROMs just like switching between browsers on a pc - today Chrome, tomorrow, Firefox and never Internet Exploder... Is that correct? It took me quite a while to get the market working and it still doesn't work optimally but I'd hate to undo all the work I've done getting the g-tab humming along by switching roms. Can I?
So - anyone care to expound on the structure and how it all hooks together? What parts can be swapped out and what parts form the foundation? I'd hate to brick the little guy in my ignorance.
One final note if you know and you answer - where did YOU learn about this. Is there a book somewhere to read?
Thanks again for sharing your knowledge.
The Need for A Wiki
I'm in the same boat as enigma. I'm not even sure what ROM is an acronym for, though I think it means operating system. A wiki would be a big help for many people. I bet people would be glad to contribute.
Well, I don't know about Android book, especially about "hacking android book" , but this (and others) forum has plenty of reading material and guides. Not to mention people (a lot more knowledgeable and experienced than me) who will offer advice and lend a hand. And Google search comes in handy too.
Switching ROMs is almost like switching the OS, or a flavor of. Very much like switching between Linux distributions; the base OS is the same, but the overlay changes the user experience. Some things do change deep down inside, that's why is advisable to clear data.
Android, like Linux which it is based on, uses separate partitions for different parts of the OS, like boot, recovery, data, cache and user data. Plenty of write ups and discussions on the web on that.
So when flashing a ROM, you'll rewrite boot and system. Your user apps and data/preferences pertaining to those apps are stored in data partition, and since you are changing the 'OS', the apps need to be recompiled for it. Backup apps, like Titanium Backup, come extremely handy here: backup and restore apps AND appdata with a few clicks.
Backups are stored on sdcard, which is a lot like Linux /home directory, and do not get wiped during flash. Also the CWM (sometimes called Nandroid) backups are also stored there. A backup-of-the-backup is always a good habit (copy of /sdcard to your PC for safekeep).
This is just a quick rundown, hopefully that answered some of the questions.
There is a world of information available out there in "ether-world", Google is your friend.
[EDIT]:
Some links:
http://android-dls.com/wiki/index.php?title=Main_Page
http://lifehacker.com/#!5596108/how-to-choose-the-right-android-rom-for-you
and of course:
http://forum.xda-developers.com/forumdisplay.php?f=841
(use the search on top of the screen)
Sent from my gTablet-TnT-Lite-4.2.5 using TapatalkPro
Doesn't my sticky on how to flash the roms help at all? I can try to make it clearer if you have suggestions.
http://forum.xda-developers.com/showthread.php?t=892090
TeamSpeed said:
Doesn't my sticky on how to flash the roms help at all? I can try to make it clearer if you have suggestions.
http://forum.xda-developers.com/showthread.php?t=892090
Click to expand...
Click to collapse
Yes, your Sticky is as clear as Florida sky.
I just installed Thumb Keyboard on my gTab last night and I guess I got carried away getting used to it!
Yes, I have found some very good step by steps (reflashed to vegan after reading that one). Step by steps are great but I 'd like to understand why I'm doing it. The market fix...I can follow the steps and it works but why? I wish I had time to research all these things but there are so many forums,so many posts to read! The explanation that did surface in this thread was great though. Thanks. I'll keep asking questions. There are a lot of smart people out there!
Context/Resume:
-I´m changing the android platform to create two partitions in a SD Card. I need to do this as early as possible. I´m currently trying at init.rc
-It would be nice to obfuscate the access to one of the partitions. If i could keep ithidden would be better
And...the long story:
I´m trying to create new partitions in a sdcard in a device, and i need to be done as early as possible. I thought that the init.rc should be the best location for this, so i tried to add a script call to perform the task, but i´m unable to create these partitions ( or get information of the reason of fail ) First of all, is this premiss valid? Should i be able to do this?
I call the script by:
service myscript /system/bin/logwrapper /system/bin/myscript.sh
disabled
oneshot
at init-time
And the content´s of the .sh file is
fdisk /dev/sdcard < mykeys.input
where "mykeys.input" is the sequence os keys used to perform the taks of create the partitions.
Well, is this the recommended way to do this?
thanks!
Not to sure bout the boot order and its effect on what you are trying to achieve. What phone and os? You might want to look at your phones logs to see in what order what/which/where is going on when. As that could explain your issues a bit more clearly and possibly even provide the mystery errors. If not try running it in an emulator where you can make the boot up verbose and boot log it.
As for hiding the partition have you tried formatting the sdcard outside the phone environment. The hiding ability should be able to be gotten if you were to format in gparted I.e. Format it how you want size wise and format wise, then for the partition you want hidden flag it lba. Not sure if lba hides from your phone or not, but worth a shot.
*edit* what are you trying to achieve again? Dual booting os on phone? If so, I would take a look more towards the /dev/loop and chmod approach. Also keep in mind if this is what you are aiming at you might want to make 3 partitions as a swap partition would be beneficial.
Sent while wearin my foam helmet ridin the short bus.
Hy blackadept:
What i want: Ensure that there is two partitions in a sdcard as early as possible. ( i must create them if needed ). My focus now is in how to create. The logic of "if/when" todo a will deal later.
Why i want this: Project requirement. Not negotiable.
What will be stored: Part1 : User acessible. Nothinf special. Part2: Special Data user by an apk.
"Phone model": It´s a tablet. STI´s tablet. Android 2.2
Well the partitions will be there just from formatting the card, as to whether or not the init sees that I am not sure. I'm one of them poor simple folk who ain't got no money....aka I don't have the fun fancy toys like a tablet. haha. Only reason I bring that up is for the fact that being as I am not around them, literally haven't even seen one let alone hold lmao, not sure how it's boot up goes.
Have you tried creating a partition and formatting it with various flags such as lba to hide it from the OS? If we are talking small sizes here then I'd think you could hide it within such a flagged partition surrounded by fluff. Throw some encryption into the mix and your gtg. At that point all that's left for you to do would be writing script to navigate the maze and unlock it. If that would work then it would be a fairly easy out.
Otherwise we could go back to the "dual booting" that I brought up in the last post. Being as my phone can't mnt to bin *droid x.....hate u Motorola* I have done all of my dual and triple boots via looping thru /dev. This could work for you as well, tho again I'm not familiar with the tablets. If you did that tho..... well you could hide it in a myriad of ways.... flags, encryption, straight up "Where's Waldo" type shenanigans....
Have you ever put an ARM OS onto an android device before? If so, maybe give it a shot and let me know? Only question I'm wondering, tho, is android's ability to see the flag and be able to handle it. Also as to the level of root that particular device has (regular not-so-super user like my phone or is it completely unlockable?) would determine a game plan too in a way. If you have full access then you could just format the card thrice (sorry always wanted to use that in a sentence and feel all smert), making a special ext3 partition with the flags or encryption, make note in the root mnt's of it's existence thru your init script (tho just giving physical note to it.... not size or content). Write your .apk or specialized script with the UUID or GUID or w/e the *beep* android uses this week, and again you win at android....
Sorry for the long winded verbal response....lately I always seem to post when I ain't slept for 2-3 days as opposed to when I ain't delirious...
Presenting Problem: Tablet is stuck rebooting itself once it gets to the booting screen animation, USB Debugging was not turned on on the tablet when it was working properly last time, and I need to turn USB Debugging on to fix my tablet. How do I do this?
Disclaimer: Yes, you'll think there are a million other threads about enabling USB debugging and whatnot, but this is totally different!
The Story: My device is a Grid10 tablet. It runs its custom OS built on Android Kernel (Gingerbread). Everything about it is android, except it's not android (and it's not a custom launcher or a skin).
... anyway
The Grid10: Almost nobody here own a Grid10 (I assume), so here's the thing... the Grid has only ONE button. The power button. No volume buttons, no home or back or menu buttons or anything... all those commands are gestures on the Grid (... if it started properly)
The Problem and its Cause: Now, It's stuck continuously rebooting itself once it gets to the the booting animation screen because I mistakenly deleted a file from system/app called SettingsProvider.apk
The Solution: I have the missing file on my laptop, and I need to put it back on the tablet. When I plug in its USB cable, I don't get a drive in My Computer. Obviously, it won't get into storage mode without being told to do so from the settings list (which I have no access to... because it's stuck rebooting itself at the booting animation screen... yes, I'm repeating myself so no one will tell me to "enable USB debugging" when I say that...)
So aparently, to get the file on my Grid, I need to use adb.
And since I didn't have USB Debugging enabled when the Grid was last operating properly, the adb can't see my tablet! (as shown by a 'adb devices' command).
The Sucky Recovery Menu: There is no fastboot on this thing (not that it would help with anything), but there is a recovery menu i can access (by holding down the power button while the tablet is booting), but it's no use. It looks like some kinda' custom recovery menu called "PBJ40 Recovery Utility". It has 4 commands:
reboot system now
wipe data/factory reset
wipe cache partition
apply sdcard: update.zip
I've tried all of these commands (selecting is done by pressing the power button, and when un-pressed for a few seconds, whatever command is highlighted gets executed).
My best bet would have been the update.zip as I created a signed update.zip with the missing file in it so it can put it back in its rightful place... but sd card in question appears to be the built-in sd card, and not the external (removable) sd card... the recovery tool doesn't even look in the external sd card for the update.zip
In Short: To get the file on the tablet, for now, the only way I can see how, is through adb, and seen as how USB Debugging was not enabled when the Grid was operational last time, I come here, to the XDA Forums, asking for advice.
The Question(s):
A) How do I turn on USB Debugging on the tablet so i can use adb and fix it?
or
B) Is there some alternative way for me to get the missing apk in system/app folder that does not require USB debugging?
Got you scratching your brain? Been trying to solve this for so long, I finished scratching mine, and started hitting it against the wall now!
I hate to tell you this man, but I am pretty sure that you messed up your tablet/bricked it.
Problem solved.
Not the USB Debugging thing, but I ended up fixing the tablet.
Can't disclose how I did it though... privacy issues.
So the system is fixed and the GirdOS is running perfectly on the Grid10, but I still can't use the tablet anyway, because of some kinda' server-side failure, because I need to register myself on the server before I gain access to any of the tablet's functions, while the server isn't responding to register my credentials... so yea... the tablet works, but it's still useless to me.
There's not much if any hope that the server will be fixed or get running anytime soon, because from the rumors/reports, FusionGarage (the producer of said tablet) has disappeared off the grid. Ironic, isn't it?
Maybe some day somebody will be able get ICS or Honeycomb running on the Grid10, and will share the knowledge-how with everybody.
I got one of those PBJ40 tablets too with 1366x768 , but no real android (just 2.1) on it.. do you mind sharing the one you got?
maybe you even have the Kernel source for this? could be nice having too
Dexter_nlb said:
I got one of those PBJ40 tablets too with 1366x768 , but no real android (just 2.1) on it.. do you mind sharing the one you got?
maybe you even have the Kernel source for this? could be nice having too
Click to expand...
Click to collapse
Explain yourself please.
What is this android 2.1 you speak of? The Grid10 (aka PBJ40) comes with its custom OS called GridOS that's based on Android.
So what's the 2.1 android you have? Is it pre-upgrade GridOS or what? After the upgrade, GridOS's kernel was made into Gingerbread.
Ghoymakh said:
Explain yourself please.
What is this android 2.1 you speak of? The Grid10 (aka PBJ40) comes with its custom OS called GridOS that's based on Android.
So what's the 2.1 android you have? Is it pre-upgrade GridOS or what? After the upgrade, GridOS's kernel was made into Gingerbread.
Click to expand...
Click to collapse
i guess hardware was tried sold to different parties, as mine is with Android 2.3 ( i made that ) but touchscreen is poor on this device, and Tegra2 got a tough time managing 1366x768 on it, compared to previous devices..
and lastly it was in development so drivers are not finished.
As your GridOS is 2.3 compatible it has a better kernel, and maybe a source for the kernel too, since i got no kernel source and no one that knows this hardware.
but maybe it'll show up with some totally different supplier, i seen talk on chinese forums where ppl compiles linux for it, so its still in the works.
Dexter_nlb said:
i guess hardware was tried sold to different parties, as mine is with Android 2.3 ( i made that ) but touchscreen is poor on this device, and Tegra2 got a tough time managing 1366x768 on it, compared to previous devices..
and lastly it was in development so drivers are not finished.
As your GridOS is 2.3 compatible it has a better kernel, and maybe a source for the kernel too, since i got no kernel source and no one that knows this hardware.
but maybe it'll show up with some totally different supplier, i seen talk on chinese forums where ppl compiles linux for it, so its still in the works.
Click to expand...
Click to collapse
I see.
Looks like whoever made the PBJ40 (aka Grid10) also sold some of its stock to other companies, and since the 'other companies' don't have a dev. team to compensate for the lack of drivers for the Tegra2 (I heard they're going to release the drivers in some 2 months), they had to sell it with Android 2.1 (froyo) on it, with lots of problems like screen responsiveness, poor power management, and the like.
I'm also guessing that you do not have Market, Talk or GMail on your tablet... or at least, you didn't have it at first (doesn't take much skill to install them... the tablet comes rooted).
I'm also guessing you have a serious gestures issue, am I right?
Do you have the 40 pin USB cable? (or did yours come with a regular female USB port??)
... I might be of assistance, if you're able to make your dev skills work in your favor.
So help me help you...
The only way this will work, is if you're able to reverse engineer the GridOS to:
1) Extract the programming that's responsible for the gestures so we can install it on any other device (like your PBJ40, which doesn't have gesture support as advanced as the Grid10), to make the device easier to use.
2) Override the sign-up screen for the GridOS. In case you do not yet know, once you boot GridOS for the first time, you're taken to a setup page (much like the setup page of Windows) where you register yourself on the FusionGarage server (people who made the GridOS) to gain access to the tablet... for some time now, the FusionGarage server has been down, and since the company recently went under, there's no way the server will be fixed ever again, so even with linux kernel 2.3 (aka android gingerbread... without the market) you can't have any kind of access to the tablet, because you'd be unable to proceed form the sign-up page forward! So if you can find a way to over-ride the sign-up page or 'delete' it from the equation altogether, we both win!
So: I can provide you with GridOS kernel version 2.3 (not android... GridOS! It's basically the same, it just doesn't have the Market, and its UI is different... still very nice... I like it).
So... you can't install GridOS on your Froyo tablet (just yet), even if you had the 2.3 GridOS at your disposal, because you'd be stuck there.
So the question remains:
- Can you reverse engineer a linux OS that is android based (but not truly android) to extract from it the gestures program so you can make your PBJ40 more responsive?
- Can you somehow customize GridOS to delete the whole signup page issue?
Both of these things will help me a lot... but only the gestures-solution will be of help to you, unless you have the USB cable for the tablet.
If you PBJ40 is not a regular Grid10, I'd like to see it from all angles + a picture of its cables and chargers... if possible, please upload them to this thread.
For now, to make your life easier, install the program called zMooth from the Market. Its gesture responsiveness will be much better than the 2.1 Froyo version your tablet is now running.
"swipe left to go back, swipe right for menu, gesture a up-arrow(^) for home"
Look at the screenshots to better understand.
While setting up the program sensitivity level, keep in mind that the lower the level, the more sensitive (it's in fine print).
... let me know what you get!
PS: It might also be of help if you can somehow get the gesture program from ICS kernel and adopt it to PBJ40!
Could be we should continue this OT, in a private PM and maybe exchange mails
I think i can do most of it, I even have Android3.0 running on it, but again kernel needed changing since touch driver is not supporting the way 3.0 works.
but it works even with highres..
I do not have 2.1 on it, i ported a CM7/2.3.6 to it, and it worked 95%, some issues with DSP manager and movie codecs, but i did not put my 100% in it, since i was doing it all for fun and my own interest, since i could not share with anyone anyways as no one had it. That was until i saw the design of Grid10, i knew it was 99% like mine.. Flash11.1 works great for movie playback here though..
I got the 4leds on it too and mine has USB HOST/device switching only by compal (writers of many tablets today), but i found the USBUTG tool to use with it, to make switching easier, than doing it in a shell.
anyways, lets maybe continue by PM.. and we can maybe exchange "partitions"
My vow of secrecy has been lifted!
To Flash your Grid10 (aka PBJ40), follow this tutorial I made:
http://www.thejoojooforum.com/viewtopic.php?f=17&t=49654
There's also more info on the general forum (and one or two other tutorials/suggestions I've made that could prove to be of benefit to anybody with a Grid10): http://www.thejoojooforum.com/viewforum.php?f=17
Ghoymakh said:
My vow of secrecy has been lifted!
To Flash your Grid10 (aka PBJ40), follow this tutorial I made:
http://www.thejoojooforum.com/viewtopic.php?f=17&t=49654
There's also more info on the general forum (and one or two other tutorials/suggestions I've made that could prove to be of benefit to anybody with a Grid10): http://www.thejoojooforum.com/viewforum.php?f=17
Click to expand...
Click to collapse
if you know how to use APX mode on it (Reset button on right side(if looking at front). I got android 2.3.6 (CM7) running on it, i think only difference is that i got 4 hardware button (soft light buttons on right side of tablet)
let me know, and i can maybe upload the kernel + system to a site.
I dnt even know what APX is!
I'm new to the android dev. scene, so i dnt know much yet.
I don't have much use for a Gingerbread ROM that's not going to be filly compatible with the Grid10. We don't have ANY buttons on our tablets.
To compensate for that, you might want to include the program Zmooth in the list of apps that the flashing-process will auto-install, so whoever flashes the CyanogenMod won't be left stranded without any buttons to use on the Grid10.
As mentioned in the flashing tutorial, V. is recompiling the original GridOS to make it skip the registration page, and it's Gingerbread too, one that's completely compatible with the tablet's specs, including gestures. It will be the GridOS as (previously) advertised by FusionGarage, only this time, no registration page, which means we can flash it and actually use it (up till now, whoever re-flashed or did a factory reset couldn't use their tablet because the registration could not be completed since the FG servers were down).
Maybe that could prove to be useful to you... I'll upload the file to the Grid10 forum once it's finished.
(i wonder if there's a way to open a Grid10 section in the xda forums...)
But what you have could be useful to somebody else out there!
How about you upload your files in Dropbox, and create a new thread on the above-linked forum, and share your ROM so other people might benefit from it.
https://www.dropbox.com/
Make sure you write your tablet's full specs, including the information about your soft and hard buttons, as our tablets have NO soft-buttons, and only have 2 hardware buttons: a power button and a reset button.
Edit: as the Grid10 doesn't have volume buttons, i don't think it's even capable of entering APX mode. It does have a recovery mode... but the only options in there are to factory-reset, delete cache partition, and install update.zip.
Ghoymakh: YOU ARE THE CLOSEST THING TO.... THX
Ghoymakh said:
My vow of secrecy has been lifted!
To Flash your Grid10 (aka PBJ40), follow this tutorial I made:
There's also more info on the general forum (and one or two other tutorials/suggestions I've made that could prove to be of benefit to anybody with a Grid10):
Click to expand...
Click to collapse
============================================
I'm one of the fortunate-unfortunates.
I previously reset my G10 and it has been useless ever since. I did however purchase the USB adapter with my device and I'm looking forward to making use of your extensive research and hard work.
Again, thanks and I'll let y'all know how it goes (within the next 7 days or so).
Praise and thanks to you and everyone else out here.
G
Ghoymakh said:
Edit: as the Grid10 doesn't have volume buttons, i don't think it's even capable of entering APX mode. It does have a recovery mode... but the only options in there are to factory-reset, delete cache partition, and install update.zip.
Click to expand...
Click to collapse
can you check when you got the tablet in front of you facing up. that on your right side a little hole is found just about center, 5-6cm above simcard slot (at least on mine simcard is on the right side)
if you turn it off, holding in the tap inside the small hole (you can feel the click when its pushed), press power and it goes into APX mode. but you will need the bootloader.bin to get it in full apx mode and ready to accept commands.
A small step for man.... My Grid10 is more than just a brick
- Using Ghoymakh's instructions from JooJoo Forum, I successfully flashed my Grid10 yesterday.
-- The identified 'tar' command didn't work on the compressed file but the Archive Mounter within Back Track worked just fine.
- Now, as time permits, I'm going to move forward and attempt to incorporate the Xmooth and Market.
-- If only I could get my JooJoo Forum account activated....
Again, Props to Ghoymakh, V, and any/all other contributors.
G
So I'm selling my old Meizu M2 Note which is running Flyme OS that doesn't allow me to encrypt the whole phone. How can I ensure the data is actually gone before selling? Normal wiping doesn't erase everything.
That's a good but hard to answer question.
A good old fashioned hard drive can be single pass overwritten (debate about overwrite passes is still an open discussion) making it unrecoverable for anything but an MFT, Mobile devices use flash memory just like a USB drive or an SSD.
What is the difference? Wear leveling (https://en.wikipedia.org/wiki/Wear_leveling).
Because of that people came up with crypto-shredding or crypto erase which only truly works with Hardware Encryption because Software encryption can never, with 100% certainty, know how the wear leveling reacts on every device.
You already said this isn't an option so what can you do to be sure nothing can be recovered? The answer is unfortunately short, nothing.
However recent research showed that multi pass overwriting caught a lot of data but even the Gutmann method (35 passes) did not get rid of everything (I forgot the link to the Whitepapers).
That said, you aren't selling it to a forensic specialist.
My best suggestion is to use one of the higher rated wiping apps (Shreddit for example) to first destroy your files, then factory reset and download a few good recovery apps and again a wiping app. Make sure you can't recover your own files anymore (if you have very sensitive data you can connect it to a PC and use even better recovery or, if you are paranoid, forensic tools) then overwrite it with as many passes, rounds and algorithms you feel comfortable with. Check recovery tools again and call it a day when you feel satisfied.
This WILL eat at the wear level so keep that in mind when you want to start overdoing it.
Not everything will be gone but it's as good as it's going to get and I highly doubt the person you sell it to will be able to recover anything.
Good luck!
GU42 said:
So I'm selling my old Meizu M2 Note which is running Flyme OS that doesn't allow me to encrypt the whole phone. How can I ensure the data is actually gone before selling? Normal wiping doesn't erase everything.
Click to expand...
Click to collapse
#noob guide incoming
(potentially useless and harmful)
i just thought of it
shred memory
download custom rom and flash
fill memory with stuff
shred again
xD
TheMarchHare said:
That's a good but hard to answer question.
A good old fashioned hard drive can be single pass overwritten (debate about overwrite passes is still an open discussion) making it unrecoverable for anything but an MFT, Mobile devices use flash memory just like a USB drive or an SSD.
What is the difference? Wear leveling.
Because of that people came up with crypto-shredding or crypto erase which only truly works with Hardware Encryption because Software encryption can never, with 100% certainty, know how the wear leveling reacts on every device.
You already said this isn't an option so what can you do to be sure nothing can be recovered? The answer is unfortunately short, nothing.
However recent research showed that multi pass overwriting caught a lot of data but even the Gutmann method (35 passes) did not get rid of everything (I forgot the link to the Whitepapers).
That said, you aren't selling it to a forensic specialist.
My best suggestion is to use one of the higher rated wiping apps (Shreddit for example) to first destroy your files, then factory reset and download a few good recovery apps and again a wiping app. Make sure you can't recover your own files anymore (if you have very sensitive data you can connect it to a PC and use even better recovery or, if you are paranoid, forensic tools) then overwrite it with as many passes, rounds and algorithms you feel comfortable with. Check recovery tools again and call it a day when you feel satisfied.
This WILL eat at the wear level so keep that in mind when you want to start overdoing it.
Not everything will be gone but it's as good as it's going to get and I highly doubt the person you sell it to will be able to recover anything.
Good luck!
Click to expand...
Click to collapse
Thanks for your amazing reply!
I finally found the solution I was looking for: as Avast! support told me, you can still use Avast! Mobile Security to securely erase your phone (by overwriting data), it's just a hidden feature. You just have to deactivate the Device Administrators permission for the app.
Then you just use the "erase device."
Was that research about multi pass overwriting done on SSD, or HDD? I always thought that one pass is enough on a standart HDD.
Can you recommend me any good forensic tools to use to check if the data is truly erased, please? And does the phone need to be rooted in order to restore deleted data?
Thanks for all your insight and advice !
GU42 said:
Thanks for your amazing reply!
I finally found the solution I was looking for: as Avast! support told me, you can still use Avast! Mobile Security to securely erase your phone (by overwriting data), it's just a hidden feature. You just have to deactivate the Device Administrators permission for the app.
Then you just use the "erase device."
Was that research about multi pass overwriting done on SSD, or HDD? I always thought that one pass is enough on a standart HDD.
Can you recommend me any good forensic tools to use to check if the data is truly erased, please? And does the phone need to be rooted in order to restore deleted data?
Thanks for all your insight and advice !
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Avasts shredder works but it's a single pass on flash memory so it doesn't clear everything with 100% certainty because of the wear leveling but no algorithm does. I'm pretty sure that's a feature they added after purchasing CCleaner.
They also added it as a module in their windows platform.
The multi pass research was done on Solid State Drives and I still can't find the link. Just from a research paper in 2011.
SSD's are still closest in comparison to the kind of memory used in Mobile devices.
As for HDD's it's an open debate. Forensics have claimed to be sble to read past 200 writes in the past but there is no research to support this. I believe that they showed that 1 pass PRNG is enough in 2005, however the DoD was still developing machines to perform 7 pass DoD standard wipes so, I have to say that I have no idea.
If you want serious forensic tools you're looking at these kind of distributions (infosec just made me laugh, SSL_ERR_CERT_COMMON_NAME_INVALID, it's infosec! ??).
http://resources.infosecinstitute.com/computer-forensics-tools/
But if anyone you sell it to would try something it would be more along the lines of Recuva and similar software.
On phones you can just download a bunch of high rated recovery tools and see if anything pops up.
You do not need root for most of them.
You could run fstrim which I'm pretty sure has no root requirements either. This would mark all blocks as invalid so Garbage Collection can pick it up as well. Even though GC has been show not to clean everything it doesn't hurt.