iPhone 12 mini Questions around Factory Reset

[mspen]

Hi,

I just wanted some clarity around resetting an iPhone to factory settings. I was under the impression there was 2 ways to do this:

1. Settings > Erase all Content and Settings: This removes all user information (it's not deleted from the device but the keys to access it are deleted) and the phone can be set up as new. The OS is not removed so if there are any issues these would remain.
2. Restore via Finder: This removes everything on the device, including all the OS and firmware, and a fresh copy of the latest iOS is installed.

By restoring it via Finder, is it true that absolutely everything is removed (unlike during an on device reset) and the iPhone can truly be set up as a new device? When downloading the latest OS, is it true that this is authorised by Apple when downloading so you can be assured that it is legit and cannot be compromised in any way? Also, I know some people put their iPhone into DFU mode when restoring via the Finder - is this necessary?

Thanks

 

[eyoungren]

I can't really answer 1 or 2, although I've always assumed with 1 that the data was also erased. However, I can say that iDevices have two partitions. They have a system partition and a user partition. All user data is stored on the user partition while the system partition is solely for the system and is normally inaccessible to the user.

Apple digitally signs iOS. If a version of iOS is no longer signed by Apple, the device cannot be restored to that version. But as long as Apple is signing it you can restore to it.

It's not necessary to use DFU, but some people (such as myself) use it because it allows direct interaction with the firmware (through iTunes).

 

[mspen]

I can't really answer 1 or 2, although I've always assumed with 1 that the data was also erased. However, I can say that iDevices have two partitions. They have a system partition and a user partition. All user data is stored on the user partition while the system partition is solely for the system and is normally inaccessible to the user.

Apple digitally signs iOS. If a version of iOS is no longer signed by Apple, the device cannot be restored to that version. But as long as Apple is signing it you can restore to it.

It's not necessary to use DFU, but some people (such as myself) use it because it allows direct interaction with the firmware (through iTunes).

Thank you.

Is there anything additional that DFU mode provides when factory resetting an iPhone through a MacBook? Or will just using the Restore option accomplish the same thing?

 

[eyoungren]

Thank you.

Is there anything additional that DFU mode provides when factory resetting an iPhone through a MacBook? Or will just using the Restore option accomplish the same thing?

Well, the Restore function doesn't always work when the phone has problems. Most of the time, DFU will. I'm no expert about DFU mode but I've had a few restores fail. Using DFU has usually fixed that.

 

[humpbacktwale]

Restore via Finder: This removes everything on the device, including all the OS and firmware, and a fresh copy of the latest iOS is installed.

Restore via finder shouldn't wipe the OS. The only way to remove the current OS is either by DFU, or by an update, whereupon the new OS replaces the old one.

As far as I am aware, the iphone firmware is iOS, given as an IPSW file.

 

[mspen]

Restore via finder shouldn't wipe the OS. The only way to remove the current OS is either by DFU, or by an update, whereupon the new OS replaces the old one.

As far as I am aware, the iphone firmware is iOS, given as an IPSW file.

When I had some iOS issues a while ago, I was told by an Apple rep that using the Erase All Contents and Settings erases the data on the phone but doesn't reinstall that version of iOS. To eliminate the software issues, I was told to Restore iPhone using my MacBook because it downloads a fresh copy of the latest OS and installs this onto the phone.

Is there a way then to completely remove everything from the phone to set it up as close to new as possible?

 

[VineRider]

When I had some iOS issues a while ago, I was told by an Apple rep that using the Erase All Contents and Settings erases the data on the phone but doesn't reinstall that version of iOS. To eliminate the software issues, I was told to Restore iPhone using my MacBook because it downloads a fresh copy of the latest OS and installs this onto the phone.

Is there a way then to completely remove everything from the phone to set it up as close to new as possible?

Put the phone in DFU mode, and select restore. This will erase the phone and download a new copy of the most recent version of iOS. The article below describes the process. Go to the section titled:

If your device turns on but gets stuck during start up​

If your iPhone won't turn on or is frozen - Apple Support

If your iPhone has a frozen screen or becomes stuck, learn what to do.

support.apple.com

 

[humpbacktwale]

When I had some iOS issues a while ago, I was told by an Apple rep that using the Erase All Contents and Settings erases the data on the phone but doesn't reinstall that version of iOS. To eliminate the software issues, I was told to Restore iPhone using my MacBook because it downloads a fresh copy of the latest OS and installs this onto the phone.

Is there a way then to completely remove everything from the phone to set it up as close to new as possible?

Yeah DFU mode would be the way to go here. Alternatively, you could Erase All Contens and Settings, then after that update the phone, which will replace the firmware with the newest version. DFU is just a manual way to do this. As far as I am aware, DFU and an update will have the same effect in regards to putting a fresh version of iOS on the phone.

 

[mspen]

Put the phone in DFU mode, and select restore. This will erase the phone and download a new copy of the most recent version of iOS. The article below describes the process. Go to the section titled:

If your device turns on but gets stuck during start up​

If your iPhone won't turn on or is frozen - Apple Support

If your iPhone has a frozen screen or becomes stuck, learn what to do.

support.apple.com

Thanks for your reply.

That article describes recovery mode which I understood allowed the iPhone to load the bootloader (which only allows the latest OS to be installed), whereas DFU mode left the screen blank and didn't load the bootloader (which allows to install older versions of iOS). Surely following the instructions in the link you provided is the same as just plugging in my iPhone and clicking on the Restore Option without putting it into Recovery mode?

Yeah DFU mode would be the way to go here. Alternatively, you could Erase All Contens and Settings, then after that update the phone, which will replace the firmware with the newest version. DFU is just a manual way to do this. As far as I am aware, DFU and an update will have the same effect in regards to putting a fresh version of iOS on the phone.

Thanks.

So if I use the Erase All Contents and Settings function, then plugging in the "erased" phone into my MacBook and clicking Restore iPhone?

 

[humpbacktwale]

So if I use the Erase All Contents and Settings function, then plugging in the "erased" phone into my MacBook and clicking Restore iPhone?

Pretty sure if you use DFU, you don't need to erase all contents and settings. It will do that anyway. DFU just allows you to manually do an "update" to another version of the firmware, while also wiping the user data. Erasing all user data, and then doing an update via your system settings, should achieve the same effect (though by all means if someone more knowledgeable has differing information please correct me)

 

[VineRider]

Surely following the instructions in the link you provided is the same as just plugging in my iPhone and clicking on the Restore Option without putting it into Recovery mode?

If it were me, and I wanted to be sure the device was completely wiped and a new copy of iOS was installed, I would use DFU mode.