Why does my iPhone 4 won’t restore and shows Error 21?
Why does my iPhone 4 won’t restore and shows Error 21?
I have been trying to restore my iPhone 4, but every attempt ends with an Error 21 message. This issue has been incredibly frustrating as my phone is essentially unusable. The process begins smoothly, but partway through the restoration, the error pops up and halts everything. I’ve tried to restart the restore process multiple times, but the same error keeps occurring. I am not sure what is causing this problem, and nothing I do seems to work. I need to understand why my iPhone 4 won’t restore and shows Error 21 so that I can get my phone back in working order. The lack of clear information on this error is making it hard to figure out the next steps.
7 Answers
The presence of Error 21 could be due to USB port issues on your computer. To determine this, try: 1. Connecting your iPhone to a different USB port on your computer. 2. Alternatively, try using a friend’s computer to see if the restore process can be completed there. If successful, this suggests an issue with the original computer’s USB ports or settings rather than the iPhone itself.
A common cause for Error 21 is outdated or corrupt iOS firmware on your device. To address this, follow these steps: 1. Download the latest iOS firmware for your iPhone 4. 2. Open iTunes and connect your iPhone. 3. Hold the Shift key (Windows) or Option key (Mac) and click Restore in iTunes. 4. Select the downloaded firmware file and complete the restoration process by following on-screen instructions.
One potential remedy involves modifying your computer’s host file, which might block iTunes from connecting with Apple’s servers. Here’s how: 1. Navigate to the host file on your computer. For Windows, it’s located in C:\Windows\System32\drivers\etc. For Mac, use Terminal and type sudo nano /private/etc/hosts. 2. Look for lines containing gs.apple.com and comment them out by adding a # symbol at the beginning of the lines. 3. Save the file, exit, restart your computer, and retry the restoration.
Error 21 may also be linked to the Apple Mobile Device USB driver malfunctioning. To fix this: 1. Ensure your iPhone is disconnected from your computer. 2. Access the device manager and locate the Apple Mobile Device USB Driver. 3. Right-click it and select ‘Update Driver Software’, choosing to search automatically for updated driver software. 4. After updating, reconnect your iPhone and attempt the restore process again through iTunes.
The Error 21 signal might stem from security software on your computer disrupting the connection between your iPhone and Apple’s servers. Try disabling or uninstalling this software temporarily. After deactivation, restart your computer and attempt the restore again. Once the process completes successfully, you can re-enable your security software.
Sometimes, Error 21 can be tackled by entering recovery mode on your iPhone and using iTunes to restore it. To do this: 1. Turn off your iPhone. 2. Press and hold the Home button while connecting your device to the computer. 3. Keep holding the Home button until the recovery mode screen appears. 4. Open iTunes and follow the prompts to restore your iPhone.
Hardware issues can also provoke Error 21. Here are some steps to diagnose these problems: 1. Inspect your USB cable for any damage; if possible, use a different cable. 2. Ensure the charging port on your iPhone is clean and unobstructed. 3. Attempt to connect your iPhone to an alternative USB port on your computer. If you’re still encountering the error, the issue might be internal, and seeking professional assistance from an Apple technician may be required.