Bios Mods -The Best BIOS Update and Modification Source

I have modified the BIOS Fujitsu PRIMERGY RX2540 M2 in order to enable PCIe bifurcation. However, when trying to flash the firmware, I am receiving an error: image signature error
How can I flash a modified BIOS file?

I tried to follow the (https://github.com/BoringBoredom/UEFI-Ed...odded-bios) in this article to change the UEFI

I have modified this section

IOU0 (IIO PCIe Port 2) | VarStore: IntelSetup | VarOffset: 0x531 | Size: 0x1
x4x4x4x4: 0x0
x4x4x8: 0x1
x8x4x4: 0x2
x8x8: 0x3
x16: 0x4
Auto: 0xFF

However, there was no effect: the NVMe disk was visible only 1 of 4 devices
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