Hello. In the links that you have gave are ROM images of openwrt-ar71xx-nand-vmlinux-initramfs.elf :
http://openwrt.ayufan.eu/rb951g/attitude_adjustment-r35508/
http://openwrt.ayufan.eu/rb951g/trunk-r35489/
As your success in flashing the RB951Ui-2Hnd with OpenWRT ?
Because after flashing with openwrt-r35489-13.0alpha1-mipsbe.npk my router begins reboot in loop and with openwrt-ar71xx-nand-vmlinux-initramfs.elf would not running.