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Last active September 12, 2022 08:23
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Enable TRIM in OS X 10.7.5 to 10.9.5

Enable TRIM on non-Apple SSDs in OS X

NOTE: This is tested on the versions mentioned in the title, and NOT earlier or later versions. YMMV.

Run the following commands in Terminal…

Backup the original driver:

sudo cp /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

Modify the driver (choose only one of the following lines, based on the version):

# 10.9.4 & 10.9.5
sudo perl -pi -e 's|(^\x00{1,20})[^\x00]{9}(\x00{1,20}\x54)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

# 10.8.3 to 10.9.3
sudo perl -pi -e 's|(\x52\x6F\x74\x61\x74\x69\x6F\x6E\x61\x6C\x00{1,20})[^\x00]{9}(\x00{1,20}\x54)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage

# 10.7.5, 10.8.1, 10.8.2
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

Run these commands in succession to clear the system caches to enable OS X to pick up the modified driver:

sudo kextcache -system-prelinked-kernel
sudo kextcache -system-caches
sudo touch /System/Library/Extensions/

Restart the Mac.

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Thank you. This help me with a MacBook late 2007 model running OS X Lion on Patriot Pyro SSD.


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Thank you it works like a charm on a 10.9.5 But if System Information says Trimm is on. Is it really on? How can I see that this is on. And by the way what does it? Randomly change the Memory Location of every bit?

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RJVB commented Apr 21, 2020

Exactly where am I supposed to see the trim enabled indicator on OS X 10.9.5?

I think I've applied the correct patch from the list above but I cannot seem to find the indicator for my external Kingston SUV500MS120G (SSDNow family).

> md5sum /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/*
79f51aaf114f3dd8be5e409f6e3c13df  /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage
ef72c0c2bfb1074bf400d3405efdae10  /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage-backup

> kextstat | fgrep -i IOAHCIBlockStorage
   61    0 0xffffff7f813bb000 0x18000    0x18000 (2.6.0) <43 16 6 5 4 3 1>

contents comparison, does this look correct?

> od -x IOAHCIBlockStorage-backup > /tmp/kk1
> od -x IOAHCIBlockStorage > /tmp/kk2
> diff tmp/kk[12]
< 0201720      0a79    4100    5050    454c    5320    4453    5400    6d69
> 0201720      0a79    0000    0000    0000    0000    0000    5400    6d69

EDIT: I just realised this patch replaces the string "APPLE SSD" with as many null bytes. I see a second occurrence of a very similar pattern a bit further in the file: "APPLE SSD TS". I guess I have nothing to lose to replace that one too (would I have an older version of the framework on my system?!)

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@RJVB You should be able to see it in System → Hardware → SATA → Trim Support: Yes

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RJVB commented Apr 26, 2020 via email

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@RJVB I've only tested this on SATA SSDs, as this was the only way to get TRIM back in the day. (Later versions of OS X supported the trimforce command.) Sorry, I don't know of a way to check if TRIM is actually working at a lower level.

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RJVB commented Apr 26, 2020 via email

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Thanks man. Worked on my evo860 SSD on my mid-2012 i5 on OSX 10.9.5 after the initial software update following reinstallation of OS X.

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