Gaining root

Solder 3 contacts GND, RX, TX to UART:

Then connect UART 2 USB adapter. To use serial console while booting, you can use minicom/picocom on Linux or PuTTY on Windows. Use baudrate 115200. Stop booting by pressing any key in the uart terminal right after powering the device. If it not stops with prompt => you should reboot the gateway by plugging it off and then on.

Prepare a new password for the root user. It can be blank, but you have to confirm it after setting it in the console.

Enter the following line and boot will start:

setenv bootargs "${bootargs} single rw init=/bin/bash" && boot

After booting to linux bash console, enter:

passwd

Enter the prepared password 2 times. In case of an empty password, you have to press enter one more time to confirm it.

NOW YOUR GATEWAY HAS ROOT

Newer firmwares can provide init script with disabled shell login on the normal start and display this message:

INIT: no more processes left in this runlevel

Enable getty on serial console. If you have an older firmware, you can run this command as well, it will run as no-op.

sed -i "s/#mxc0/mxc0/" /etc/inittab && sync

To enable ssh server on the gateway add the following line at the end of /etc/rc.local before the /home/root/fac/fac_test line:

/etc/init.d/dropbear start &

Now you can reboot and connect to your gateway at *GATEWAY_IP*, port 22.

If you receive an error:

Starting Dropbear SSH server: Pseudo-terminal will not be allocated because stdin is not a terminal.
ssh: connect to host rsa port 22: Connection refused

It means that your dropbear is compiled without ssh-server support and can serve only as a client. Replace it with a fully functional ssh-server:

mv /usr/sbin/dropbearmulti /usr/sbin/dropbearmulti.backup
echo -e "GET /openlumi/openlumi.github.io/master/files/dropbearmulti HTTP/1.0\nHost: raw.githubusercontent.com\n" | openssl s_client -quiet -connect raw.githubusercontent.com:443 -servername raw.githubusercontent.com 2>/dev/null | sed '1,/^\r$/d' > /usr/sbin/dropbearmulti
chmod +x /usr/sbin/dropbearmulti

Setting Wi-Fi without Mi Home app.

You can omit this section in case the gateway is already connected using Mi Home application.

After rebooting, the gateway enables the testing console. To exit to normal login mode, type exit_factory, then press enter.

Then log in to the console with the user root and password you have set.

How gateway enables Wi-Fi

While booting, gateway while executing rc.local it runs the lines:

/home/root/set_mac.sh &
/lumi/app/miio/wifi_start.sh > /dev/null 2>&1 & 

Those lines check for the file /lumi/conf/wifi.conf and if it is absent, it starts an open Wi-Fi Access Point.

Creating Wi-Fi config

Run the following lines with your own Network name and password. Keep key_mgmt as is:

echo 'ssid="lao_mao"' > /lumi/conf/wifi.conf
echo 'psk="12345678"' >> /lumi/conf/wifi.conf
echo 'key_mgmt=WPA' >> /lumi/conf/wifi.conf

Also, you can use vi editor to set Wi-Fi credentials:

vi /lumi/conf/wifi.conf

Press i, then paste

ssid="lao_mao"
psk="12345678"
key_mgmt=WPA

Then exit with saving: (Press Esc, then type :qw and press Enter)

To check the config is correct you can manually run the lines from /etc/rc.local:

/lumi/app/miio/wifi_start.sh 

You will see the connection process. Press ctrl+c after you got the info if the device is connected or not. If the Wi-Fi credentials are set correctly, ifconfig will show IP address of the gateway.