Builing costum U-boot bootloader for HLK-7628N

I’m trying to replace the u-boot bootloader of the HLK-7628N with a custom one, but I receive an error when trying.

I have made the image by using the OpenWrt repository and the u-boot-2022-1 directory in it.

First step of building the uboot image was setting the defconfig.

make mt7628_rfb_defconfig

Set the custom settings of the bootloader with:

make menuconfig

Then build it with:

CROSS_COMPILE=~/openwrt/staging_dir/toolchain-mipsel_24kc_gcc-11.2.0_musl/bin/mipsel-openwrt-linux- make -j$(nproc)

If I take the u-boot.bin file on the HLK-7628N and run the following script line.

mtd write /etc/bootloader/u-boot.bin u-boot

Then I received the following error.

Could not open mtd device: u-boot

Does anyone know how to make a valid version of u-boot for the HLK-7628N?
Thank you for your effort.

I'm sure partition name is not u-boot but uboot
Please check cat /proc/mtd output