EDK2 NV variable can not be saved correctly in Flash #148

Hi,
I am trying to debug the EDK2 Uiapp menu using the spl + opensbi + edk2(as opensbi payload) + linux5.15 + busybox boot flow on starfive-VisionFive2. I flash all of them into SDcard and set bootmode to SDIO.

I have noticed that if I save NonVolatile variables (such as BootTimeOut) in Uiapp and then directly reset, the variable saving works fine. However, if I enter linux, power off, and then power on again, the variable is restored to its default value (or erased).

In EDK2, the flash offset for saving NV variables is 0x800000:
gJH7110TokenSpaceGuid.PcdSpiVariableOffset|0x00800000

which does not overlap with the mtd partition in the dts:

			partitions {
				compatible = "fixed-partitions";
				#address-cells = <1>;
				#size-cells = <1>;

				spl@0 {
					reg = <0x0 0x40000>;
				};
				uboot@100000 {
					reg = <0x100000 0x300000>;
				};
				data@f00000 {
					reg = <0xf00000 0x100000>;
				};
			};

Is it the SPI-NOR flash driver that affects the nonvolatile variable, or is there some other reason?

Does anyone know what might be causing this issue?