What is an error code 4045 when trying to update Iphone 12 on a PC in recovery mode?

Troubleshooting:

Turn your iPhone on and unlock it -> enter the passcode.

Go to Settings -> set Auto-Lock to Never.

Connect your device to your computer using an Apple USB cable & try also another USB cable.

(macOS) -> Make sure your Mac has the latest version of macOS or the latest version of iTunes.

(Windows OS) -> Make sure your Windows PC is up to date.

See also -> Check your third-party security software.

Check the Wi-Fi connection.

Turn Off Hotspot.

Turn Off or remove VPN if necessary.

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See this Apple article: iOS update and restore errors

iOS update and restore errors – Apple Support (UK)

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See -> If you see error 9, 4005, 4013 or 4014 when you restore your iPhone, iPad or iPod touch

Check your USB connections

If you see error 4005, 4013 or 4014, use these steps.

If you see one of the errors below, check your USB connection, USB cable, USB port or computer:

• 13, 1600, 1601, 1602, 1603, 1604, 1611, 1643-1650
• 2000, 2001, 2002, 2005, 2006, 2009
• An error that includes "invalid response"

Here's what to check. Try again after each step:

1. Use the USB cable that came with your device. If you don't have it, try a different Apple USB cable. 
2. Switch to a different USB port on your computer. Don't plug into your keyboard.
3. Switch to a USB port on a different computer.
4. If you still see the error, check for other USB issues, check your third-party security software, then check your hardware.

If you still see an error, contact Apple Support.

If you continue to see error 9, 4005, 4013 or 4014 when you try to restore your iPhone, iPad or iPod touch, contact us.