iPhone won't stay in dfu mode long enough to restore?
When I put my iPhone in dfu mode, connect it to iTunes and start the restore process. It reboot it's self
1) download directly the official firmware
Remember where you saved this.
2) Put phone after you finished downloading into DFU mode, open iTunes, and i will ask you to restore.
3) On PC Hold SHIFT+ Click the restore button. On MAC, Hold OPTION + Click the Restore button.
4) Itunes will now let you choose an IPSW file. Choose the one you downloaded in Step1. Restore should then start.
For some reason iPhones have an annoying habit of rebooting while you're waiting for the firmware file to download. Thankfully, you can download the firmware file through your browser and select it manually in iTunes, so the phone doesn't have to wait for iTunes to download 2.5+ GB.
Go to https://ipsw.me/ , locate your model and download the latest IPSW (Apple's iOS firmware file type). ipsw.me links to Apple's firmware servers, so the latest versions are digitally signed, which means you can use them in iTunes.
Put your phone into recovery mode and connect it to your computer. Cancel any dialog options asking if you want to restore or update until you are at the phone's landing page. There should be two buttons on the righthand side of the iTunes window marked "Check for updates" and "Restore iPhone..." On Mac, hold down the "alt/option" key while left-clicking on "Restore iPhone...", and you'll have the option to choose the firmware file you wish to restore with. On Windows, hold down the shift key while clicking "Restore iPhone..."
Select the firmware file you downloaded from ipsw.me and the phone should restore. Doing it this way allows you to download the file prior to putting your phone into recovery mode, so it won't timeout and reboot while iTunes is doing its thing.
Thank god that actually worked. My iphone 6 while trying to update to ios 12 would go into recovery mode and not come out of it. Then i would get it into DFU only for it to reboot and turn on half way through while updating on itunes. I couldnt even force the update ota because the ‘checking for update’ would just spin and think but not freeze. This is the only option that has worked! Thank you and kudos to you!
I have the ultimate answer to this problem. I could restore my iPhone, which was not even detected by iTunes yesterday. When the software is being downloaded in my case through Finder, before the time is up for the DFU mode and the phone exits the DFU mode simply press the home button+power button combination followed by the home button only so the phone restarts the DFU mode. That way you can prolong the amount of time your phone stays in DFU mode and when the download is completed, you are good to go.