How to Enable JIT on iOS 17+ iDevices

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Enabling JIT in Xcode for iOS 17+

Applicable for iOS versions below 17 as well.

Prerequisites:

• A Mac [or potentially a VM, though untested]
• Xcode installed

Steps:

1. Install/Update Xcode: Ensure you have the latest version of Xcode. Install or update it via the Mac App Store if needed.
2. Open a Project: Either start a new Xcode project or open an existing one. Any iOS project language works.
3. Connect Your iOS Device: Use a USB to connect your iOS device to the Mac. Trust the device if prompted.
4. Add Device in Xcode: Go to the [Window] tab, select [Devices and Simulators] [Shortcut: Shift + Command + 2].
5. Attach Debugger: Under the [Debug] tab, choose [Attach to Process by PID or Name]. Enter the App's executable name and click [Attach] You can find executable name by extracting IPA file and locating it inside the Payload folder.
6. Run the App: Open the app on your iOS device. Xcode should automatically begin attaching, enabling JIT.
7. Detach Debugger: Go back to the [Debug] tab and select [Detach].
8. Disconnect the iOS Device: Unplug your device from the USB. JIT is now enabled for iOS 17+.

Troubleshooting:

1. Debugger Not Attaching to Application:
   • There are several reasons why this issue might occur:
     • Check Executable Name: Verify that the executable name of the app is entered correctly in the [Attach to Process by PID or Name] section.
     • USB Connection: Ensure that the USB connection between your iOS device and the Mac is secure. This is especially important for iOS 17+ devices.
     • Restart Xcode: Sometimes, simply restarting Xcode can resolve this issue. Close and reopen Xcode, then try the steps again.
     • Trust the Computer: If your iOS device prompts you to trust the computer, make sure to accept it to allow the debugger to attach.
2. [Attach to Process by PID or Name] is Grayed Out:
   • If this option is not available, consider the following:
     • Unlock iDevice: Make sure that your iOS device is unlocked when you try to attach the debugger.
     • Device Recognition: Confirm that your iOS device is properly added and recognized in Xcode under [Devices and Simulators]. If not, add it through this section.
     • Restart Xcode: As with many technical issues, restarting Xcode can sometimes fix this problem. Close Xcode and reopen it, then reattempt the steps.
     • Check Connection: Ensure that your iOS device is properly connected to your Mac via USB.
3. If these steps do not resolve your issue, you may need to consult the Xcode documentation or seek support from Apple's developer forums for more specific troubleshooting related to your setup.