I will answer in English and Portuguese. Please bear with me.
The tp_recovery.bin image is a openwrt image plus the bootloader, suitable for installing via tftp, as this is the easiest method to install the image. Once this image is installed you can create others, copy over and install via sysupgrade. To install via TFTP you need to install a tftp server on your computer, set the address on the computer to 192.168.0.66 and turn on the router with the reset button pressed. Your computer should be connected to one of the LAN (yellow) ports on the router. You will see the led flashing rapidly as the image is transferred. DO NOT TURN OFF THE ROUTER. Change the address on your PC to 192.168.1.2 and ping 192.168.1.1. Once it starts pinging you can turn off the router.
Portuguese:
Esta já é a imagem do openwrt para você instalar via TFTP. siga as intruções acima (coloque um servidor tftp no seu computador, coloque seu computador no endereço 192.168.0.66, ligue o 849 com o botão de reset apertado). Pronto, o openwrt está instalado. Aí você pode fazer o que quiser com ele, inclusive instalar outra imagem, se bem que para o 849v6 ainda não tem imagem oficial. Eu vou por a minha lá quando tiver tempo.
--schara