K4 Password lost-does factory resetting overwrite data?

lostpasswordguy · 11-21-2020, 01:20 AM

Please excuse me if this is the wrong subforum to post in, it seemed like the best fitting place on mobileread and I think developers may have useful knowledge here.

I set a password on my non-touch kindle 4 (D01100) and forgot it. I have notes on an ebook which I didn't buy from amazon, so the notes aren't in amazon's cloud. I would like to recover those notes very much. I haven't modified the kindle in any non amazon approved way, so it seems my only options are to guess my password or to reset my kindle.

When you reset a kindle, does it overwrite your personal data? Or simply mark the space where it is stored as available? In the latter case, I should hopefully be able to recover my notes by resetting the kindle, imaging it, and using data recovery software? I'd appreciate any help or tips, I have searched google and this forum and have found no info on what I could do on an unjailbroken device without a password.

NiLuJe · 11-21-2020, 10:56 AM

A factory reset will wipe user data. And, IIRC, you can't image it *first*, because a locked Kindle doesn't export over USBMS.

IIRC, there used to be a backdoor in the passcode lock... but that very well may be one that immediately triggered a factory reset, so it won't help you (because it might have been RESETME or something).

(If, on the other hand, you had shell access, then it'd be trivial to bypass, but you don't).

lostpasswordguy · 11-21-2020, 09:02 PM

Quote:

Originally Posted by NiLuJe

A factory reset will wipe user data

Indeed, but does it overwrite it? If I understand linux correctly, when a file is deleted is not overwritten as a rule. The storage area is simply marked as available, in which case I'd hopefully be able to recover my data by imaging the drive in the kindle after resetting it. Would anyone be kind enough to back up their data, reset their kindle 4, and image it to see if your files are recoverable?

NiLuJe · 11-21-2020, 10:55 PM

It's not a file deletion: the partition is wiped. Which, granted, is actually slightly better for us here, since IIRC it just stomps on the partition table a bit, because remember that all of this runs on the worst filesystem of all times: FAT32.

On a K4, you're probably mostly safe. You'll have to abort the setup ASAP, which is a bit tricky, because before a certain point, the Kindle won't export anything over USBMS.

IIRC, the sweet spot is right around when it starts asking about Wi-Fi, but it's been ages since I've done this, so, here be dragons.

But even in the best of cases, you probably won't be able to recover everything.

lostpasswordguy · 11-28-2020, 10:56 AM

Update: I was able to recover the notes! Resetting the kindle indeed simply clears the partition table. For whatever reason none of the recovery software I used was able to find the notes files, but I knew that notes in the file were separated by a series of 10 '=' chars so I searched for that pattern and the first match was my file

NiLuJe · 11-28-2020, 11:20 AM

Yep, when all else fails, hexdump & dd to the rescue ;p.

11-21-2020, 01:20 AM	#1
lostpasswordguy Junior Member Posts: 3 Karma: 10 Join Date: Nov 2020 Device: Kindle D01100	Password lost-does factory resetting overwrite data? Please excuse me if this is the wrong subforum to post in, it seemed like the best fitting place on mobileread and I think developers may have useful knowledge here. I set a password on my non-touch kindle 4 (D01100) and forgot it. I have notes on an ebook which I didn't buy from amazon, so the notes aren't in amazon's cloud. I would like to recover those notes very much. I haven't modified the kindle in any non amazon approved way, so it seems my only options are to guess my password or to reset my kindle. When you reset a kindle, does it overwrite your personal data? Or simply mark the space where it is stored as available? In the latter case, I should hopefully be able to recover my notes by resetting the kindle, imaging it, and using data recovery software? I'd appreciate any help or tips, I have searched google and this forum and have found no info on what I could do on an unjailbroken device without a password.

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11-21-2020, 10:56 AM	#2
NiLuJe BLAM! Posts: 13,478 Karma: 26012494 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	A factory reset will wipe user data. And, IIRC, you can't image it first, because a locked Kindle doesn't export over USBMS. IIRC, there used to be a backdoor in the passcode lock... but that very well may be one that immediately triggered a factory reset, so it won't help you (because it might have been RESETME or something). (If, on the other hand, you had shell access, then it'd be trivial to bypass, but you don't).

11-21-2020, 10:55 PM	#4
NiLuJe BLAM! Posts: 13,478 Karma: 26012494 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	It's not a file deletion: the partition is wiped. Which, granted, is actually slightly better for us here, since IIRC it just stomps on the partition table a bit, because remember that all of this runs on the worst filesystem of all times: FAT32. On a K4, you're probably mostly safe. You'll have to abort the setup ASAP, which is a bit tricky, because before a certain point, the Kindle won't export anything over USBMS. IIRC, the sweet spot is right around when it starts asking about Wi-Fi, but it's been ages since I've done this, so, here be dragons. But even in the best of cases, you probably won't be able to recover everything.

11-28-2020, 10:56 AM	#5
lostpasswordguy Junior Member Posts: 3 Karma: 10 Join Date: Nov 2020 Device: Kindle D01100	Update: I was able to recover the notes! Resetting the kindle indeed simply clears the partition table. For whatever reason none of the recovery software I used was able to find the notes files, but I knew that notes in the file were separated by a series of 10 '=' chars so I searched for that pattern and the first match was my file

11-28-2020, 11:20 AM	#6
NiLuJe BLAM! Posts: 13,478 Karma: 26012494 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	Yep, when all else fails, hexdump & dd to the rescue ;p.