How to completely format an iPhone/iPad?

bcodemz

macrumors member
Original poster
May 6, 2014
46
40
Hi,

There has been a lot of complaints about iOS lagging, and I feel it as well.

TL: DR: my 2 year old rMBP became increasingly laggy over time, especially with animations. Reinstalling OS X does little to help, but a complete format + install OS X made a night and day difference in smoothness and speed. I noticed the same thing on iOS. How do I format an iOS device?

I've noticed something interesting. I've had a 2014 rMBP, and it has ran slower and laggier over the years. It has gotten so slow and laggy that many times I hated my MBP and wanted to go back to Windows. I finally decided to do something when I used a brand new rMBP, and it was completely smooth, and it ran so much faster it was literally a night and day difference when the hardware difference is minimal.

So I decided to reinstall OS X since back in the old days reinstalling Windows can make your computer much faster. I originally did a reinstall in recovery mode, which just reinstalled OS X and left my apps and files intact. This did little to help with the smoothness and speed issues. I think it did improve a little, but it might be placebo.

Then I decided to do a completely clean reinstall of OS X. I formatted my drive clean, and then installed a fresh copy of Yosemite on it. The result? The improvement in smoothness and speed is night and day. This is what a Macbook should be. The animations are perfectly smooth. Safari tabs open instantly. Everything is snappy.

I noticed the same thing on iOS. I remember getting my iPhone 5C at first with iOS 8, and it was ridiculously snappy. It is noticeably slow now with some stutter in the animation when it should be improved in iOS 9. I've moved on to a iPhone 5S now, and I got it with iOS 9, and it was very snappy as well. But just a couple of months of use the phone noticeably slowed down. Most notably, the keyboard takes a second or two to pop up when before it popped up instantly.

So, I think the cure is to completely format the phone and put iOS back on again, just like what I did for my MBP. How would I do that?
 

Shirasaki

macrumors G3
May 16, 2015
9,429
3,442
Uh, maybe, without proper hardware equipment, there is no viable way to firmly format the flash on an iOS device.

And what I say "proper hardware" is using hardware method to wipe out everything stored on flash.
 

gobikerider

Suspended
Apr 15, 2016
2,022
1,469
United States
Hi,

There has been a lot of complaints about iOS lagging, and I feel it as well.

TL: DR: my 2 year old rMBP became increasingly laggy over time, especially with animations. Reinstalling OS X does little to help, but a complete format + install OS X made a night and day difference in smoothness and speed. I noticed the same thing on iOS. How do I format an iOS device?

I've noticed something interesting. I've had a 2014 rMBP, and it has ran slower and laggier over the years. It has gotten so slow and laggy that many times I hated my MBP and wanted to go back to Windows. I finally decided to do something when I used a brand new rMBP, and it was completely smooth, and it ran so much faster it was literally a night and day difference when the hardware difference is minimal.

So I decided to reinstall OS X since back in the old days reinstalling Windows can make your computer much faster. I originally did a reinstall in recovery mode, which just reinstalled OS X and left my apps and files intact. This did little to help with the smoothness and speed issues. I think it did improve a little, but it might be placebo.

Then I decided to do a completely clean reinstall of OS X. I formatted my drive clean, and then installed a fresh copy of Yosemite on it. The result? The improvement in smoothness and speed is night and day. This is what a Macbook should be. The animations are perfectly smooth. Safari tabs open instantly. Everything is snappy.

I noticed the same thing on iOS. I remember getting my iPhone 5C at first with iOS 8, and it was ridiculously snappy. It is noticeably slow now with some stutter in the animation when it should be improved in iOS 9. I've moved on to a iPhone 5S now, and I got it with iOS 9, and it was very snappy as well. But just a couple of months of use the phone noticeably slowed down. Most notably, the keyboard takes a second or two to pop up when before it popped up instantly.

So, I think the cure is to completely format the phone and put iOS back on again, just like what I did for my MBP. How would I do that?
I always do a DFU restore it reloads a fresh copy of the firmware and iOS
 

Armen

macrumors 604
Apr 30, 2013
7,375
2,207
Los Angeles
Hmm. Still hard to know if this is a full disk format.
OP requires something like that for a cleaner system install. And maybe garbage cleaning as well.
But it looks like DFU cannot exactly achieve this goal.
Well, a DFU restore requires iTunes to restore so I'm thinking it does blow out the partitions on your phone.
 

rigormortis

macrumors 68000
Jun 11, 2009
1,813
229
when you do a dfu, all it does is replace iOS . it doesn't write over the users data.

there is no need to "completely format" an iOS device. you must be living in the world of android

when you erase an iPhone 3GS or later, it removes its 256 bit decryption key ( for example : .ryJ9G~nWmt5pf?nC.F,y'y??qNjt~be ) from what apple calls ' effaceable storage ' which is a part of the iPhone that apple believes that can not be recovered. what is left over is unreadable unless you wrote down the key or know of some weakness with aes-256 XTC

a 256 bit key has 3.02285533000820708504E+111 combinations. however, because you used the ascii character set, it might be lowered to 1.93711484458501E63, heh


I've heard rumors that once you jailbreak your iPhone, you're basically screwed, because it might be possible for your decryption key to be saved offline. and someone might be able to recover the lost data.

flash memory can never be truly securely erased. all you can do is encrypt it and then erase it and forget the key or physically destroy the phone. those anti virus people had a field day buying up old android phones from eBay and retrieving all kinds of personal info, and those phone owners believed they were doing a ' full format '
 
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zorinlynx

macrumors 603
May 31, 2007
5,548
6,513
Florida, USA
OP is probably thinking of something like the equivalent of TRIMing the entire flash disk, which no, you can't do.

I imagine iOS handles this sort of thing automatically.