Sorry, I just see your reply, here i give some clue:
First, you need an usb with gpt format so you can Create the OS X Installer. Then install clover to usb, in this step, you should check Install for UEFI booting only. After that, you can copy my attachment content overwrite your clover.Second, when boot your dell, press F2 to enter bios and set loader to uefi and uncheck the lagacy mode, uncheck the secure boot, uncheck the all vt things too. After that, save your bios change, and reboot your computer. if all that you do right, you will see enter clover screen.
Last, in clover screen, select your osx installer disk all enter ei capitan install, after install complete, the computer will restart then in clover screen, select your hdd to enter your hackintosh.
All thing is done, at this moment, hd520 is not perfect, even if you set ig-platform-id is 0x19160000 in config.plist, but you can use it normally if you select right display profile. you can do this in System Preferences, Displays, Color, Display profile.
Hope this can help you, have a good luck.
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