Enable TRIM in OS X 10.8.2

os-x-enable-trim.txt

Enable TRIM on non-Apple SSDs in OS X 10.8.2 Mountain Lion.

WARNING: This is ONLY tested on 10.8.2, and NOT earlier or later versions. YMMV.

Technical note: The driver changed in 10.8.2 and similar perl commands that worked in earlier OS X versions did not work for me once I updated to 10.8.2.

Run the following commands in Terminal…

1. Backup the original driver. Added -p to preserve original metadata about the file
    sudo cp -p /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage ~root/IOAHCIBlockStorage-original
    sudo echo /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage > ~/root/IOAHCIBlockStorage.original.path
    sudo cp -p /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage-backup

    cp -p ~root/IOAHCIBlockStorage.trim-enabled /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage-backup

2. Modify the driver

    sudo perl -pi -e 's|(\x52\x6F\x74\x61\x74\x69\x6F\x6E\x61\x6C\x00{1,20})[^\x00]{9}(\x00{1,20}\x4D)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

2a. Attempt to make it look like we were never here:

sudo touch -acfm -r /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage-backup /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

3. 2 commands to clear the system caches to enable OS X to pick up the modified driver

    sudo kextcache -system-prelinked-kernel
    sudo kextcache -system-caches

4. Restart the Mac

Has this been tested on 10.8.2 12C60?

@itavero sorry I didn't see you comment until now. I have been using this with 12C60 for about 5 months and have had no discernable issues. Seems to be working well... Finding this is a good reminder of not updating to 10.8.3 until I find if there are any changes required and corresponding updates to this script.