PC Games Hardware (PCGH) discovered that certain AMD Radeon RX 9070 graphics cards can be flashed with the video BIOS of RX 9070 XT of a comparable board design, to achieve higher clock speeds and power limits. While the flash won't unlock any new shaders—you're still limited to 56 CU or 3,584 stream processors—it gives the RX 9070 increased power limits and clock speeds of the faster SKU. More importantly, the flashed RX 9070 was found to offer significantly improved overclocking headroom, and PCGH was able to tune up performance by 15-20% over stock RX 9070, bringing its performance to match a stock RX 9070 XT, which was confirmed by a set of 3DMark benchmarks.
There are, however, some caveats. The most obvious one is that BIOS flashing is fraught with risks, and unless you have a card with dual-BIOS, you really need to know what you're doing. Secondly, BIOS flashing might only work between two cards that share a common board design. AMD board partners tend to use nearly identical board designs between the RX 9070 and RX 9070 XT, at least for the value segment SKUs. And lastly, there is no software tool that can flash Radeon RX 9000 series GPUs yet, the modder used a hardware flashing tool that interfaces with the 8-pin BIOS ROM chip on the card. The flashed card does not display "XT" in the name string.
Update 13:23 UTC: Our resident hardware guru W1zzard has the following explanation for why the card's name does not change. On AMD cards, the revision ID field is used to distinguish between variants of the same GPU. On the RX 9070 Series, the XT models uses "C0" and the non-XT uses "C3." In the past, the AMD BIOS stored the revision ID of the card, and flashing the BIOS would change the value that Windows sees, and thus the model name will change accordingly. With Navi 4x, AMD made a change to their BIOS format, so that the revision ID can no longer be changed, which protects against fake cards, but in this case it means that some properties like power limits, clocks, etc. can swap to values from the BIOS, but all the IDs and unit counts remain fixed.