First off, let me apologize if this is the wrong place for this.

After upgrading my gpu from a sapphire rx480 nitro 8gb to the above listed (primary reason: 4x dp output so I can drive both my zisworks
monitors in 4k120hz at the same time), I noticed some oddities to it: in any pre-os situation (post/bios menu/grub/etc), I have no output on
any of the dp ports (dp ports are important because the zisworks monitors only have dp, two each in fact). In fact I had no output over hdmi.

Googling around for a solution I came across this forum's UBU and GOP_Updater tools. Using both of those to update the graphics related
stuff to the latest available version gave me hdmi output, but still no dp output. Was hoping someone could perhaps elaborate and give me
some ideas on where to go next. I did report the bug to amd but no response as of yet.

Just a quick bumperino, I'm still stuck in this situation. Currently reverted to stock bios on both gpu and mobo.

@hanetzer - If you updated the graphics card GOP, then nothing you can do except talk directly to the manufacturer of the card (not AMD, unless it's an AMD branded card?)
How are you booting, UEFI I assume, but do you have secure boot enabled, what about CSM? Try with secure boot disabled and CSM enabled/disabled, any change?

Motherboard BIOS does not matter here, in regards to updating GOP or vBIOS etc, those modules are for the onboard graphics only.

Do still have the RX480? If yes, dump it's vBIOS, and then include your GOP updated vBIOS, put in a zip, and upload to the vBIOS/GOP update thread and ask if someone can look for you why DP works on the RX480 but not on the RX5700
Maybe @Sylar76 can help there, or here, but he'll need to have both vBIOS first before he can tell you anything.

You may have to jump on ebay and find some HDMI >> to >> Dual Mini-DP adapter or something?