In principle, there is nothing complicated in rolling back the factory settings to the iPhone 4s, but often when they are restored through iTunes, unforeseen problems can occur, for example, a strange error 29 appears.
This is a rather unpleasant and common bug that can occur not only when the settings are rolled back, but also when updating, flashing, synchronizing, and just turning it on. Why is this happening and what to do in this case?
Does this article help you? 
Other similar problems can occur only in a few minutes. 
There are probably many conflicts arising under startup errors. An update requires internet access. Check the list of antivirus locks for such a case or just turn it off for a while. 
Problems can occur with voltage management on older computers with very old motherboards. Sensor cables serve for different purposes, but very often, due to the lack of a sensor cable, it leads to an error.
What does error 29 mean?
The cause of this error may be:
- A common system failure - therefore, flashing or repeating the recovery procedure can fix the problem.
- Old version of iTunes - error 29 is highly probable.
- Battery failure is a very common cause.
- Problems with the bottom loop.
- There is a problem with the power chip.
Error 29 while restoring iPhone - fix method
Method number 1
The easiest and most affordable method - if recovery was done through a computer, you need to restart the operating system, reconnect the smartphone to another USB port, if possible with a different cord, and repeat the recovery procedure again - it often helps.
Unscrew the battery to turn off the power, and when you see the sensor cable, pull it out, clean the connectors and reinstall everything in order. Do not complete this step if you do not think you can do this. 
Now turn on the device and connect it to the computer. Conclusion
This error usually occurs because some security software package interferes with recovery, and it is usually easy to fix. Solution 3. Solution 5: Check the sensor cable. Keep the power button pressed for 3 seconds.
Method number 2
Before trying to restore the settings again, you need to make sure that the problem is not in the software. ITunes version should be the freshest - therefore, if necessary, it should be updated. Also, it is worth paying attention to the version of the operating system. Only the latest versions of these programs can guarantee a successful rollback to the factory settings.
Getting started with fixing error 21
It says that the device was not recognized correctly. There are several ways to fix this problem. We will show you which ones. Follow these steps.
Error 21 during maintenance
In this state, recovery or update should work without problems. . The best time battery life is hoping for the majority, like almost every year.In the first generation, the battery does not last 24 hours, despite moderate use. Other options that are being discussed are sleep and smart straps with additional sensors for tracking fitness. It could be an application or something else. Or do retailers expect a new device in less than 90 days?
Method number 3
You can try disabling the antivirus program and the firewall. If it doesn’t help, it might be worth trying to redo the procedure on another computer and a little later.
Additional measures
What else can cause this error and what can be done?
Battery Replacement / Repair
As already mentioned, a frequent reason due to which error 29 may occur is a faulty or non-original battery. Therefore, in the event of its occurrence, the battery changes, and, most importantly, that it was produced at the factory, and not in the Celestial Empire. Although, most likely - this is a myth so that consumers buy expensive original batteries. But for those who do not want to take risks, acquiring an unknown battery, here are the numbers that should be present on native batteries: 616-0580, 616-0579, 616-0581.
Standard Reset Method
First, make sure your battery is small, ideally more than 80%. Then check if you are connected to the Internet. Finally, it is important that you have a backup of your data, because recovery deletes all information on your device, such as photos, documents, videos, messages, etc.
Creature backup security. Make sure you have the latest version installed on your computer. If you need to update, download latest version. Wait for the backup to complete. System restore to default.
Moreover, the original battery on the iPhone will be needed only for the time of flashing or rollback settings - then you can return the old battery, if it is, of course, in working condition. In theory, the error should not appear. But how to understand that the matter is in it - after all, buying a new battery is not cheap, but it may not be in it. Of course, you can ask a friend for a battery, if there is one. In other cases, you can try to assess the condition of the battery yourself.
Another option for advanced users
If so, you need to disable the “Activation Lock” function on mobile device. After that, follow these steps to restore the system to default. Connect the device to the computer using the cable that came with it.
Using DFU Mode
A confirmation window opens informing you that all data on your device will be deleted. Click Restore and Update to confirm. Wait for the recovery to complete. This may take several minutes. Connect the device to the computer with backup.
It should be noted right away that assessing the battery’s performance is not so simple, but still it makes sense to try. Here, some special applications will come to the rescue.
Battery Life - after installation on the smartphone screen, you will see how much the battery has worn out. There are four modes: excellent, good, bad and very bad. Also, you can check how many times the charge was made.
Select your device and click the “Restore” button. Error messages during recovery. If after following the above recommendations you receive an error message during recovery, do the following: Please note that your computer is updated with the latest operating system updates.
Restart your computer and try again. As a rule, updates or restorations do not generate errors, but may occur in some cases. IN following lines we will see the most likely causes, as well as ways to solve them, in order to continue to work normally with our devices.
iBackupbot is a computer / laptop application. To check, a smartphone or other device running on iOS is connected via a usb cable, after which it starts already installed application, and in the Devices / Devices section, a specific gadget is selected. After that, all the technical data on it will be shown. If you click on the More Information button, you can see how many times the battery was charged. If the amount has already exceeded a couple of hundred - it is worth thinking about buying a new battery, and it is likely that the cause of error 29 is in it, although not a fact.
Best of all, they are points that almost anyone can follow. regular user computer, and in most cases solve the problem. Error 53 is displayed if the security test for the device is inconclusive. But the story around this dysfunction does not seem to have ended. The case concerns the refund process and the guarantee, in particular, mention of problems related to “Error 53”. When you receive this error, the following error message is displayed.
Happened unknown error. We have already analyzed several of these questions in the article, so let's look at this because you will already find some useful tips. Below we show 6 more possible jams to solve the error. # 1: cleaning the computer registry.
And again, even if these applications show that the battery, so to speak, “breathes in the air”, you should not rush to throw it out and run to the store for a new one. You can try to give a chance to the old - for this it is calibrated.
What is the essence of the procedure? The fact is that over time, the controller, which is responsible for the battery charge, starts to fail, often not charging it enough. And often this happens during flashing or other similar procedures, which leads to the appearance of error 29. And the calibration procedure will allow you to “reset” this controller.
After cleaning, restart your computer and try restarting the device again. # 2: delete unwanted files. There are so many cache files and log files that accumulate over time in operating system. You can do this by clicking the “Start” button, typing “update” in the search box and pressing “Enter”. After that, select “Install Updates” from the “Update” window. Drivers can stop working completely for several reasons. This can help fix the error. How to fix error 53 in these cases?
Just use the old button, and then try rebooting the device. The “Unknown Error 53” problem may also be caused by improper screw placement during screen replacement. If you insert the longest screw into the wrong hole, it may damage one of the layers on motherboard. In these cases, there is no way to solve the problem.
The sequence of actions is simple:
- It is necessary to completely discharge the battery (all the way) - music, video, games will definitely help;
- Now that the battery is guaranteed to be “dead”, the smartphone is being charged, preferably from the network - this will provide a better charge. After its level reaches 100% - you need to support the smartphone a little more on the network for fidelity;
- Next, the first two points are repeated again. You must not break the technology - otherwise it will fail.
That's it, now that the battery is fully charged again, you can try to do the recovery procedure and check for errors. Did not help? Then you have to buy or look for a new battery.
As mentioned above, updating the firmware is the main cause of this error. Then release the two buttons and the logo will disappear. Try to check its integrity or try replacing it with another. We have already proposed a solution to reboot the device. A similar thing would be with a computer.
The initial screen of the program. Usually these are professionals who perform executive or managerial work. You do not need to worry about it because it is not critical error, and there are several solutions to eliminate it. Now that we’ve found out what the problem is, let's see what are the possible solutions. Before resorting to more extreme measures, such as restoring your device, you should try some initial steps.
Cleaning up the hosts file
When the firmware is not produced properly, the occurrence of error 29 during the restoration of factory settings is not ruled out. And sometimes when trying to correctly flash a smartphone, the same notorious 29th error occurs. In this case, fixing the hosts file will help. What kind of file is this? It is contained in the operating room. windows systemand iOS on smartphones from Apple. One line in this file can block access to Apple servers during a flashing.
If you have little storage space, you can try using third-party applications. If none of the previous tips worked, you should restart your device. Now you can select the files to be backed up. This screen will open.
Select error or message number
Select a mistake to find out what you need to do. Wait for the download to complete and try again.
Checks security software
Here is what you need to check. Try again after each step. If you see one of the errors below, it could be a hardware problem.Why? Yes, because the firmware must be supported by Apple servers. If so, they sign it with a special hash and send it to iTunes. If unsupported firmware was installed, then probably the TinyUmbrella program was used, which was registered in hosts file a string redirecting iTunes to the Cydia server.
It was done, but then when trying to install fresh firmware, an annoying nuisance may arise - Cydia servers do not yet have this version of the firmware, updates arrive there late. As a result, the operation fails and an error message appears.
Is this extortion decryptable? To get a detailed report and detailed analysis of your system, use a free scanner. To restore the necessary system components, please purchase a licensed version of the recovery tool. This amount is extremely large, and we believe that no one wants to pay that amount of money, especially for cybercriminals who illegally encrypt the victim’s personal files.
System Restore Point Recovery
Open the program and run a computer scan to detect encrypted files. Install the program in accordance with the instructions provided. . If the virus does not accidentally delete these copies, you can quickly restore the files. Open the program, and then use the menu in the upper left corner to select the drive on which the encrypted files are stored.
- Install it in accordance with the instructions given in its installer.
- Select your preferred folder and click Export.
- Select the location where you want to save the recovered files.
What to do? Accessing it on Windows is not so difficult - just drive the file name into the search, and then edit it using a simple notepad. If the operations are carried out directly from the smartphone, it is possible that a special program will be required to search, open and edit the hosts file.
You can recommend a convenient file manager for devices running under iOS - iFunBox. It is installed directly on the computer - the interface is intuitive, so find desired file will not be difficult. Mac example:
File recovery with data backup
First of all, you want to make sure that the virus does not try to spoil backup data. Therefore, remove the virus using anti-malware tools such as.
Automatic recovery of files and other system components
- Once you get rid of the virus, connect the backup disk to the computer.
- Import files by dragging them to your computer.
On an iPhone, the hosts file is in the same folder (etc). Now you need to find the line 74.208.10.249 gs.apple.com - the whole problem is in it. It can simply be removed or put in front of it # lattice. And so that TinyUmbrella’s flexible intellect doesn’t spell out its line again - prevent it from doing this by unchecking Set Hosts to Cydia on Exit.
We tested each of these programs and their effectiveness for you, so all you have to do is let these tools do all the work. We can be associated with any product that we recommend on the site. This patented recovery process uses a database of 25 million components that can replace any damaged or missing file on the user's computer. To restore damaged system, you need to purchase a licensed version of the malware removal tool.
These methods can be applied even by a relatively inexperienced user, but sometimes the reason is more complex breakdowns, for example, a malfunction of a cable with a connector or a power chip. In this case, it is not recommended to try to repair your fourth iPhone yourself - it is better to contact specialists.
All iPhone users are often faced with the fact that there is a need to update the phone. The update traditionally takes place through a program on the computer called iTunes. But what to do if you just put your iphone or iPad on recovery or the update is almost over, but then suddenly a failure appears on the screen: “iPhone“ iPhone ”cannot be restored. An unknown error occurred (21). ” What could be the reasons that could not be restored iphone 4s or iphone 4 and error 21 prevented us? How can I fix this error myself? We will try to help you with this article.
Error 21 when restoring iPhone 5 and 5s
Certainly apple produces products that are very rarely amenable to impact and time and breakdowns they happen less often than in other phones, but alas, there are problems here, they are most often found in iPhones 4 and 4s.
What can cause error 21?
The error itself carries the concept of a device malfunction. Therefore, first of all, make sure that all communicating devices are working.
- Incompatibility of devices
- Incorrect connection
- USB port malfunction;
- Use of a non-original charger;
- Phone crash;
- Outdated smartphone updates
How to fix the problem?
Another option for advanced users
Another reason why the “iTunes could not restore iphone 5 error 21” problem could occur could be caused by the failure of the DFU mode during jailbreak, and this is exactly the way by which the user can fully access all smartphone files completely.
To fix this problem, you must use special program redsn0w_win_0.9.15b3, with it you can restore the phone using DFU mode. To do this, use the following instructions:
- You need to connect a smartphone to your computer with using USB, and then launch Aityuns.
- The next step is to hold the main key and the power key for about 10 seconds.
- The next step is to release the power button, but still hold the main key until Aityuns detects your iPhone, which is in a recovery state.
- Now the smartphone is in the process of DFU, nothing should be displayed on the display.
- Being in this state, Aityuns will still perceive an iPhone on data recovery. Once you see error message 21 again, start IPSW recovery
- At the end of the process, this problem should no longer be displayed on the screen.
If not one of these methods could not solve this problem, then we advise you to contact a service center. Because the smartphone could be damaged from the slightest fall. It is possible that damage to certain internal parts of the smartphone has occurred or some individual parts have burned out and without the look of an experienced wizard you will not recognize this problem.
