iPhone 5 or earlier iPhone 5C not installing iOS 10.3.3

[magicMac]

I had a working iPhone 5C 16GB running iOS 9.3.1 I use as a basic work phone, but needed to update to iOS 10.3.3 to support some apps and fix a GPS issue apparently. This is the last signed and supported iOS release for the iPhone 5C.

It kept failing OTA, just after verifying so never really started the update. Tried downloading multiple times from different WiFi networks, not sure why - might be failing some certificate validation perhaps related to the GPS shift in November 2019.

Anyway I have tried doing the update from iTunes on PC and from a mac and this was looking more hopeful but it keeps getting stuck at one of the last steps installing and verifying the firmware (baseband?). On PC it gives me error -1 and on mac it gives me "The iPhone could not be updated. An unknown error occurred (50). 1303.FFFF". All signs point towards the baseband chip but it was a working phone so I don't believe this is true. I think iTunes might be trying to install the same firmware as iPhone 5 but actually the 5C has the same baseband modem as 5S (supporting LTE band 20 unlike the iPhone 5).

Unfortunately iTunes has now bricked it because until this is resolved I cannot boot into iOS 9 either. When I turn it on all I get is connect to iTunes message. Anyone else had this issue installing legacy iOS version on a legacy device? Hoping someone out there has come across this unusual problem, or at least advise on how I can go back to 9.3.5 (finding the software file and getting it to pass certification, as it's not signed anymore for the iPhone 5C AFAIK). It would be a shame to through it away, the battery life and external condition of the phone is nearly perfect, and is very nice to carry around as a second phone (small)

Frustrating that a simple iOS update can break an otherwise working phone, albeit old. Should have left it on iOS 9 but hindsight is a wonderful thing...

 

[now i see it]

Look up DFU restore

 

[eyoungren]

I had a working iPhone 5C 16GB running iOS 9.3.1 I use as a basic work phone, but needed to update to iOS 10.3.3 to support some apps and fix a GPS issue apparently. This is the last signed and supported iOS release for the iPhone 5C.

It kept failing OTA, just after verifying so never really started the update. Tried downloading multiple times from different WiFi networks, not sure why - might be failing some certificate validation perhaps related to the GPS shift in November 2019.

Anyway I have tried doing the update from iTunes on PC and from a mac and this was looking more hopeful but it keeps getting stuck at one of the last steps installing and verifying the firmware (baseband?). On PC it gives me error -1 and on mac it gives me "The iPhone could not be updated. An unknown error occurred (50). 1303.FFFF". All signs point towards the baseband chip but it was a working phone so I don't believe this is true. I think iTunes might be trying to install the same firmware as iPhone 5 but actually the 5C has the same baseband modem as 5S (supporting LTE band 20 unlike the iPhone 5).

Unfortunately iTunes has now bricked it because until this is resolved I cannot boot into iOS 9 either. When I turn it on all I get is connect to iTunes message. Anyone else had this issue installing legacy iOS version on a legacy device? Hoping someone out there has come across this unusual problem, or at least advise on how I can go back to 9.3.5 (finding the software file and getting it to pass certification, as it's not signed anymore for the iPhone 5C AFAIK). It would be a shame to through it away, the battery life and external condition of the phone is nearly perfect, and is very nice to carry around as a second phone (small)

Frustrating that a simple iOS update can break an otherwise working phone, albeit old. Should have left it on iOS 9 but hindsight is a wonderful thing...

You can't go back if it's unsigned. Well, not easily anyway. You could probably do it via jailbreaking but this is a work phone, right?

Anyway, try cutting out the middle man and go direct.

Turn the phone off and plug it into the computer (after turning it off)

Open iTunes.

Follow these instructions to place the phone in DFU (Direct Firmware Upgrade) mode:

Entering DFU Mode (Official Instructions)

1. Hold the Power button for 3 seconds. (This will turn the phone on and is what you want at this point)
2. Hold the Home button without releasing the Power button for 10 seconds.
3. Release the Power Button but keep holding the Home button.
4. Keep holding the Home button until you are alerted by iTunes saying that it has detected a device in Recovery Mode

If you successfully enter DFU mode the screen of the iPhone will be blank.

Once iTunes detects the iPhone in recovery mode (with the screen blank, no iTunes symbol) THEN try an upgrade and restore.

Let us know if it works.

PS. My iPhone 5, which is older than your 5c, is running iOS 10.3.4. So, this may also be due to the firmware you (or iTunes) is downloading. You want to be sure that your Mac or PC is running the latest version of iTunes.

 

[magicMac]

You can't go back if it's unsigned. Well, not easily anyway. You could probably do it via jailbreaking but this is a work phone, right?

Anyway, try cutting out the middle man and go direct.

Turn the phone off and plug it into the computer (after turning it off)

Open iTunes.

Follow these instructions to place the phone in DFU (Direct Firmware Upgrade) mode:

Entering DFU Mode (Official Instructions)

1. Hold the Power button for 3 seconds. (This will turn the phone on and is what you want at this point)
2. Hold the Home button without releasing the Power button for 10 seconds.
3. Release the Power Button but keep holding the Home button.
4. Keep holding the Home button until you are alerted by iTunes saying that it has detected a device in Recovery Mode

If you successfully enter DFU mode the screen of the iPhone will be blank.

Once iTunes detects the iPhone in recovery mode (with the screen blank, no iTunes symbol) THEN try an upgrade and restore.

Let us know if it works.

PS. My iPhone 5, which is older than your 5c, is running iOS 10.3.4. So, this may also be due to the firmware you (or iTunes) is downloading. You want to be sure that your Mac or PC is running the latest version of iTunes.

Hi Eyoungren,

thanks for the detailed reply, it's really helpful. For reason, I'm having a lot of trouble getting it into DFU mode, but I will keep trying...

Seems no matter what combination of buttons i press and hold, it just goes from apple logo straight to "connect to iTunes" picture

 

[eyoungren]

Hi Eyoungren,

thanks for the detailed reply, it's really helpful. For reason, I'm having a lot of trouble getting it into DFU mode, but I will keep trying...

Seems no matter what combination of buttons i press and hold, it just goes from apple logo straight to "connect to iTunes" picture

The instructions I provided are via iFixit, which may not be the best.

Here's my usual link.

I haven't done this in a while so the usual link didn't come up at the top of the Google search results. Note, it will say iPhone 6s or below. That's you.

Again, start with the iPhone off but connected to the computer and iTunes open.

 

[winxmac]

iOS 9.3.6 and iOS 10.3.4 are the ones with GPS fix

iOS 10.3.3 is the highest version for iPhone 5c

You may want to uninstall iTunes and download and install at least version 12.6 or go with the latest iTunes

Try downloading IPSW using Apple direct links from sites like theiphonewiki and ipsw.me