Use OpenIV and extract dlclist to your desktop from: \Grand Theft Auto V\update\update.rpf\common\data\dlclist.xml
   Open dlclist with notepad, and add this new line:

                <item>dlcpacks:\r8\</item>

   Save it, and replace the original dlclist with this one using OpenIV



Use OpenIV and extract extratitleupdatedata.meta from: \Grand Theft Auto V\update\update.rpf\common\data\extratitleupdatedata.meta 
   open it with notepad, and add theses new lines:

 <Item type="SExtraTitleUpdateMount">
<deviceName>dlc_r8:/</deviceName>
<path>update:/dlc_patch/r8/</path>
</Item>


Save it, and replace the original extratitleupdatedata.meta with this one using OpenIV