My landline NBN VDSL internet connection speed is pretty limited. The maximum sync speed I can achieve is only around 30Mbps. With the rollout of 5G around the country, a lot of telcos in Australia is starting to offer 4G mobile broadband plans with generous 500GB per month data caps. I have been really tempted to jump onto 4G to use as my house internet connection instead. Doing a speed test on my phone on 4G at various times for the past few days, I can get about 100Mbps off-peak and around 65-80Mbps during peak hours.
I looked around for a suitable 4G gateway modem/wifi router but found the choices a bit of a compromise, some 4G gateway modems have limited configurable options and others have speed caps baked into their firmware. Also, some telcos will limit your speed if they detect that you are using a router device as opposed to a phone.
I have a few older S905x Android TV boxes with 1GB ram lying around which I stopped using because running dodgy Android firmware with 1GB ram is frankly subpar. I have been repurposing them for various purposes like running Home Assistant and pihole. They are pretty good for those applications, pretty much anything you would run using a Raspberry PI, you can do it better using one of these Android TV boxes. I will be showing you how to install OpenWRT onto one of these boxes.
For the actual 4G modem part, I will be using an old Android phone that I am not using anymore, a Samsung Galaxy Note 5 running in USB tethering mode. You should be able to use any old Android phone. In this configuration, I can eventually upgrade the setup to a cheap Android 5G phone later when 5G becomes available in my area. As a side note, network unlocked 5G gateway modem is non-existent at the moment.
Hardware requirements:
1. S905/S905x/S905w/S912 Android TV Box. If you are buying a new Android TV Box, I recommend getting one with a gigabit LAN port as your internet connection may be limited by the LAN port connection.
2. Android Phone
3. MicroSD card, preferably Class 10 and above.
4. RJ45 Cat5 and above network cable, which is your typical LAN network cable. Cat5e and above if your LAN port is a gigabit port.
5. USB cable to connect the Android TV box to the phone.
6. TV with spare HDMI input
Optional hardware:
1. USB Keyboard
Software requirements:
1. Download the OpenWRT firmware for your Android TV Box:
2. Rufus or balenaEtcher to burn the firmware onto the microSD card.
Instructions:
Section 1: Prepare the MicroSD card
Step 1: Go to https://pulpstone.pw/openwrt-18-06-2/ and download the firmware under SBC that has S905x in it.
Step 2: Burn the image onto the microSD card using Rufus or balenaEtcher.
Section 2: Prepare the Android TV box
Step 1: Insert the microSD card you prepared in Section 1 into the Android TV box.
Step 2: Connect the Android TV box to the HDMI input of your monitor/TV and the LAN port of the Android TV box to your laptop/PC LAN port. If you have a PC and cannot move it to the TV, you can unplug and move the Android TV box to your PC after Step 5.
Step 3: You need to boot into the recovery mode of your Android TV box. Some Android TV boxes have a reset pin hole, you will need to hold it down while plugging in the power to get it to boot into recovery mode. If your Android TV box does not have a reset pin hole, boot into the TV box and there should be an “Update” or “Update & Backup” app under “Apps”. Select any zip file and click “Update”. It doesn’t matter which zip file you select, but you do need a zip file to select to trick your Android TV box to boot into recovery mode. In extreme cases, where there is no zip file for you to select, you will need to insert the microSD card back into your computer and just create an empty text file and call it dummy.zip.
Step 4: When the Android TV box boots into recovery mode, there should be a whole bunch of text flying past your screen.
Step 5: Wait for the text to finish loading, which is after a few minutes and the text has totally stopped flying up your TV.
Step 7: Plug your 4G Android phone into any USB port of your Android TV box. Under notifications, you should be able to select what mode the USB connection should be. Select “USB tethering”. Turn the Android phone Wifi off, so that it is using 4G to access the internet.
Step 8: You should be able to surf the internet through the Android phone’s 4G connection.
At this point, if you are reading up to here, you might be thinking, this seems like a lot of work when I can just use the 4G Android phone in Wifi hotspot mode.
From this point onwards, I am extending the setup to share the 4G connection with the rest of the devices in my house, both wired and wireless.
Section 3: Setting up the Android TV box as the main network gateway
Step 1: Check the DHCP range of main wifi router. For my wifi router, the setup is this:
IP Address: 10.0.0.138
DHCP Range: 10.0.0.1 to 10.0.0.137
Note: if you are not familiar with networking, a typical wifi router can theoretically issue 253 IP addresses to clients. This is limited by the way IP addresses are organised, where each number before the dots can only range from 1 to 254. My wifi router has a non-common IP address of 10.0.0.138. Common wifi router IP addresses are usually 192.168.0.1 or 192.168.1.1, so your router IP address is probably one of the 2 IP addresses.
Step 2: Pick an IP address outside of the DHCP range. In my case, I chose 10.0.0.139.
Step 3: Log into the Android TV box web interface. Open a browser window on your computer and type in 192.168.1.1. The default username is root and the password is also root.
Step 4: On the left hand navigation, click on Network > Interfaces. You should see the one that says “LAN” under the Interfaces window. Click on Edit.
Step 5: Under this General Setup tab, the only thing you need to change is the “IPv4 address”. But in case the options are different, the other important options should be:
Protocol: Static address
IPv4 address: {IP address you have chosen}
IPv4 netmask: 255.255.255.0
IPv4 gateway: {leave blank}
Step 6: Click the “Save” button in the bottom right corner. You can also click “Save & Apply”, but sometimes there are problems with saving option in OpenWRT, so I always click “Save” and then “Save & Apply” just to be on the safe side.
Step 7: After you saved and applied the changes, the IP address of the Android TV box is now 10.0.0.139 or the IP address you had chosen. The page may stop loading, because the IP address is no longer 192.168.1.1. Wait for a few minutes, and then type in 10.0.0.139 or the IP address you had chosen.
Step 8: Go back to the “Interfaces – LAN” screen by clicking on Network > Interfaces > LAN > Edit.
Step 9: Now we need to turn off the DHCP server on the Android TV box, otherwise it will clash with your main wifi router when you plug the Android TV box into your network. At the bottom of the screen, you will see a section called “DHCP Server”. The first option is “Ignore interface”, tick it. Then click “Save”, then “Save and Apply”.
At this point, you are ready to plug the Android TV box into your main network.
Section 4: Change main router settings to use Android TV box as the internet connection
Step 1: Plug the LAN network port of the Android TV box into a spare LAN port on the main router.
Step 2: Open the settings page of the main router. There are too many different brands and they all have different interfaces. You need to find the settings section where the DHCP settings are kept. Under the Network gateway/Internet gateway/Gateway setting, set it to the Android TV box IP address, which in my case is 10.0.0.139. Save the setting.
You can now unplug your wired internet connection and see if you still have internet. If not, reboot your router for the new settings to take effect.
Note: