Is it possible to get the iOS 5.1 SDK for Xcode 4.2 on Snow Leopard?

Question

To get Xcode 4.2 on Snow Leopard to run code on a device running iOS 5.1 you can do this:

1. If you have another Mac running Lion and Xcode 4.3.1 you can copy the files from:

   /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176)

2. Place the copied files in the equivalent place on your Snow Leopard Mac: probably

   /Developer/Platforms/iPhoneOS.platform/DeviceSupport

3. Similarly copy the iOS 5.1 SDK files found in this directory:

   /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk

4. Also copy 'version.plist' from the Lion machine in the iPhoneOS.platform folder to the Snow Leopard machine.

5. Re-start Xcode on the Snow Leopard machine and re-connect the devices and it seems happy enough.

If you don't have access to a machine with Lion and Xcode 4.3.1:

1. You can get the files out of the 4.3.1 DMG which can be downloaded from Apple here: Downloads for Apple Developers.

2. Mount the DMG, Show Package Contents on the Xcode icon and drill down to

   /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport

3. Follow the steps above.

You might find it more convenient to use Apple's proprietary ditto method (sudo ditto src dest) in the terminal window to copy the folders.

Note,this hack will also work for latest iOS 6 SDK.

You have to get Lion, iOS 5.1 SDK is only for Xcode 4.3.1 which is only available for Lion.

... and your Xcode will not be able to build to your device if you have already updated it to 5.1 because it won't be on that version of Xcode's approved SDKs

I'm working on this now. I have the same issue.

The MAJOR PROBLEMS here are that:

1) Apple never provided a warning dialog that this might disable people developing under Snow Leopard.

2) There is no easy way to undo this.

3) This should not happen on a point release update.

I've tried to install the previous ipsw from 5.0.1 for my Gen 4 IPod Touch from here: where to download ipod touch firmware restore links It will not install.

I've downloaded the Lion Xcode 4.3.1 from here (sign in as a developer first) Lion Xcode 4.3.1

And run some scripts from the Dev Forums here:

sudo cp -R /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/
sudo cp -R /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator5.1.sdk /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/

sudo cp -R /Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1\ \(9B176\) /Developer/Platforms/iPhoneOS.platform/DeviceSupport/
cd /Developer/Platforms/iPhoneOS.platform/DeviceSupport/

sudo rm -f ./Latest

sudo ln -s ./5.1\ \(9B176\) ./Latest

Unmounted the Lion DMG and restarted Xcode. This allowed me to test 5.1 in the simulator but broke every build to every device with a SIGABRT or link error.

I'm off to the Apple store to have them restore my device. If I get any more information, I'll let you all know. This has been a VERY EXPENSIVE and VERY UNPLEASANT surprise.

Adding to Richards solution above, I found that if you also copy, from XCode 4.3.1 dmg...

edit: updated to correct path within dmg

/Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Develope‌​r/SDKs/iPhoneOS5.1.sdk ~~ (entire directory tree)

to

/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/

XCode debugger will startup correctly (without all the error log and dumps)

ie:
===============================================================================
warning: Unable to read symbols from "dyld" (prefix __dyld_) (not yet mapped into memory).
warning: Unable to read symbols from "SystemConfiguration" (not yet mapped into memory).
warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176)/Symbols/System/Library/Frameworks/MessageUI.framework/MessageUI (file not found).
warning: No copy of dyld found locally, reading from memory on remote device.  This may slow down the debug session.
warning: No copy of <No file name> found locally, reading from memory on remote device.  This may slow down the debug session.
warning: No copy of <No file name> found locally, reading from memory on remote device.  This may slow down the debug session.
warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176)/Symbols/System/Library/Frameworks/SystemConfiguration.framework/SystemConfiguration (file not found).
warning: No copy of SystemConfiguration.framework/SystemConfiguration found locally, reading from memory on remote device.  This may slow down the debug session.
warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176)/Symbols/System/Library/Frameworks/MessageUI.framework/MessageUI (file not found).
warning: No copy of MessageUI.framework/MessageUI found locally, reading from memory on remote device.  This may slow down the debug session.
warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176)/Symbols/System/Library/Frameworks/AudioToolbox.framework/AudioToolbox (file not found).
warning: No copy of AudioToolbox.framework/AudioToolbox found locally, reading from memory on remote device.  This may slow down the debug session.
warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176)/Symbols/System/Library/Frameworks/iAd.framework/iAd (file not found).
warning: No copy of iAd.framework/iAd found locally, reading from memory on remote device.  This may slow down the debug session.
warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176)/Symbols/System/Library/PrivateFrameworks/SpringBoardServices.framework/SpringBoardServices (file not found).
warning: No copy of SpringBoardServices.framework/SpringBoardServices found locally, reading from memory on remote device.  This may slow down the debug session.
warning: Unable to read symbols for /Developer/Platforms/iPhoneOS.platform/DeviceSupport/5.1 (9B176)/Symbols/System/Library/PrivateFrameworks/FTClientServices.framework/FTClientServices (file not found).
warning: No copy of FTClientServices.framework/FTClientServices found locally, reading from memory on remote device.  This may slow down the debug session.
===============================================================================