DSDT.aml (Differentiated System Description Table) is a file used to tell OS X how to locate and enable features of your computer mainboard without checking of BIOS. It can be placed at the root of your system hard drive or in /Extra folder which depends on your installation method.
It’s possible to tweak Os X system in all sorts of ways by changing lines of code in the DSDT.aml file. Unfortunately, you can’t just open this file in TextEdit. First you must extract your DSDT.aml, convert it to DSDT.dsl, then edit it and recompile it to DSDT.aml. To make it easy there is a GUI application that allows you to do all of this in one editor.
This method will work both on Lion and Mountain Lion hackintoshes.
To Extract DSDT you should run DSDT editor after the install, when you start the Os X from your USB bootloader (Do not extract it if booted from hard drive, and if already using DSDT.aml cause it wont work). So first unzip and than open DSDT editor. System will automatically ask to instal Java (if it’s not already installed), so just accept it and wait DSDT Editor to open.
From upper Mac menu under DSDT Editor select File / Extract DSDT.
Once you extracted your DSDT click Patch from upper menu and press Open, select patch for your motherboard open it and than press Apply, wait till finished and than press Close Patch. (if you need to apply more patches just repeat this step again).
Now, again from upper menu, press IASL and select compile, and than press Fix Errors if any and close Compile.
Again press IASL and now select Save AML as and save it as DSDT.aml to your desktop (if you will use MultiBeast for after install upper letters are required). Otherwise, you can name this file dsdt.aml and possibly copy it to root of your’s system hard drive, all depends on your method of installation.
That’s it, now its time to use MultiBeast with selected “UserDSDT or DSDT-Free Installation” which will use the DSDT.aml file on desktop and will copy it to /Extra folder.
Follow some of this tutorials to complete your installation:
Installation of Retail OS X 10.8.2 Mountain Lion on Gigabyte GA P41T-D3P
Installation of OS X 10.8.2 Mountain Lion 64bit on PC based computer