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Why does my Radeon RX 9060/9070 fail to boot on my X99 motherboard (Code D6 or Black Screen)?

I have several of these new cards from PowerColor, and none of them work on my X99 system, but they work on LGA1200 and LGA1700. What is the reason for this, and can it be fixed?
Answer

The Short Answer: This is not a fault of your X99 motherboard. The blame lies entirely with specific graphics card vendors (e.g., Sapphire, PowerColor, Gigabyte). Their VBIOS (firmware) implementation is often “lazy” and lacks the proper initialization code required for older HEDT platforms like LGA2011-3. They likely only validated these cards on modern consumer platforms.

Important: Changing motherboard BIOS settings will not fix a black screen (Code d6) if the GPU’s firmware fundamentally refuses to initialize during POST.

💡 The Exception: ASRock

ASRock engineers correctly implemented the legacy initialization code. Therefore, ASRock RX 9000 series cards almost always work on X99 “out of the box.”

Note that newer revisions from other vendors manufactured after April 2025 may ship with a corrected VBIOS, but this still requires practical verification.

Solution 1: The “Swap” Method

If you are still within the return window, return your current card and exchange it for an ASRock model. This is the only guaranteed solution that does not require voiding your warranty or risking hardware damage.

Solution 2: Cross-Flashing VBIOS (Expert / High Risk)

If you cannot return your card, the only way to get a video signal is to replace its firmware with the ASRock version.

You can find the compatible ASrock VBIOS on TechPowerUp: RX 9060 XT, RX 9070, RX 9070 XT.

Before you proceed, head over to TechPowerUp and see if there is a newer vBIOS specifically for your card. If your manufacturer has already released an update, flashing that is much safer than forcing a BIOS from a different brand.

⚠️ WARNING:

  • Warranty Void: Tampering with firmware immediately voids your warranty.
  • You can attempt to cross-flash using a modified amdvbflash tool to bypass ID checks. However, if the flash results in a black screen, software recovery is impossible. A hardware programmer  is essential to have as a backup to unbrick the card.

Recommended BIOS Settings (Post-Fix)

Once you have a working display (either by swapping to ASRock or successfully flashing the VBIOS), you must apply these settings in your Motherboard BIOS for stability:

  • 1. Above 4G Decoding: Set to Enabled.
    Critical for the large memory address space required by the RX 9000 series.
  • 2. CSM (Compatibility Support Module): Set to Disabled.
    Forces the motherboard into pure UEFI mode, which is required for Resizable BAR and modern driver stability.
  • 3. PCIe Configuration:
    Path: IntelRCSetup > IIO > [Your GPU Port]
    — Link Speed: Force Gen3.
    — Link Width: Force x16.
    Prevents signal drops, stutters, and driver crashes under heavy load.