By the way, it sounds like you have a standard partition layout,
and no modifications have been made to it.
I would recommend the following:
- Use the bootloader (FIP,
mt7981_ax3000t_an8855-fip-fixed-parts-multi-layout.bin
) I mentioned earlier. - Boot it into recovery mode and simply flash the
openwrt-mediatek-filogic-xiaomi_mi-router-ax3000t-squashfs-sysupgrade.bin
file through its web interface.
What you'll get: a working OpenWrt.
What you won't get: U-Boot.