smartino

Bash scripts for installing Bitcoin Core on Android and run a full node on a phone!

That's possible because:

• you can run Ubuntu (or other distro) in your Android phone thanks to Andronix
• you can attach an external drive to the phone using a USB hub or insert an high capacity MicroSD card

Why a full node on a phone

You can run a full node on a laptop and have the comfort of having screen and keyboard, not to mention to have a battery backup in case of a power cut.
You can run a full node on a Raspberry Pi or other single-boar computer and have advantages such as less space required and less electricity demand.
With a phone you run a full node and you can get all the pros of both laptop and Raspberry Pi. In addition a phone offers ubiquity and portability!

Based on...

Installation is based on the process described in this tutorial (found here), which in turn is a modified version of BitNodes.io script.

Here are some enhancements:

• Added a more reliable probing strategy for detecting external storage
• *Added the ability of connecting external drive having already blockchain data (".bitcoin" folder)
• Harden the externalization of Bitcoin Core data directory
• Updated Bitcoin Core version
• Added a couple of shortcut commands
• Fixed some typos in comments and messages
• Some other small improvements

*It may be not recognized by Android. Please be aware Android supports exFAT/NTFS/EXT4/F2FS partitions up to version 8.1 (Oreo)

Requirements

• Android phone with OTG support or high capacity MicroSD support
• Root privileges
• 1 TB external storage (no more than one connected to the phone)
• USB hub to connect both phone charger and external drive to the phone

WARNING: The use of low-quality chargers/USB cables, or with specifications that differ from those indicated by the manufacturer, may damage the phone's battery.
Ensure that the phone indicates that the battery is charging when the charger is connected via the USB hub; otherwise, it is advisable to change the hub. If the battery icon does not show charging status, the recharging process may still occur, but there is a risk of damaging the battery to the point of causing it to swell!

Root privileges

If you are not able or do not want to root your phone you can use the original guide that works - according to what the author says - only with some Samsung models having DeX support. Actually root is not required only in case Termux app mounts your removable/external drive under /storage path. In that case you have write access to drive but with a limit: the only writable location on the external drive is Android/data/com.termux/files, a private Termux directory. If this trade-off is ok for you then you can go for original guide and waive the enhancements described above.

Installation

• Connect the external drive to the phone and be sure you can open it with a file explorer
• Install the latest version of Termux
• Run the following command (it will basically install Ubuntu on your phone), answer "y" to all questions and allow Termux to have access to the storage:

pkg upgrade && termux-setup-storage && curl https://raw.githubusercontent.com/AndronixApp/AndronixOrigin/master/repo-fix.sh > repo.sh && chmod +x repo.sh && bash repo.sh && pkg update -y && pkg install wget proot tar tsu mount-utils -y && wget https://raw.githubusercontent.com/smartm0use/smartino/main/install-ubuntu20.sh -O install-ubuntu20.sh && chmod +x install-ubuntu20.sh && bash install-ubuntu20.sh

• Be sure you got no errors in mounting external drive, then run the following command from Ubuntu shell (it will install Bitcoin Core and it will set the datadir to the external drive):

apt update && apt upgrade -y && apt install curl -y && curl https://raw.githubusercontent.com/smartm0use/smartino/main/install-full-node.sh | sh

• For incoming connections to your node be sure you've configured your router for port forwarding (port 8333) and optionally to change your firewall settings
• Once your node is fully synced with the blockchain visit Bitnodes to check connection

EXTRAS - Give more power to your node!

Remote access using SSH

If you find awkward tapping on a small screen, you may consider to get remote access to your phone following SSH Basics by Andronix or these steps:

• apt update
• apt install openssh-server nano
• nano /etc/ssh/sshd_config and make the following changes:
  • Find and change the line #Port 22 to Port 2222
  • Find the line #PermitRootLogin prohibit-password or #PermitRootLogin yes and change it to PermitRootLogin yes
  • Save and exit pressing CTRL+X and then type Y and press Enter to confirm
• ssh-keygen -A and then ssh-keygen
• Set user password with passwd (minimal length is 1 character)
• /usr/sbin/sshd to start the SSH server (if you get Missing privilege seperation directory: /run/sshd just create that directory with mkdir /run/sshd and run the command again)
• hostname -I or ip a or ifconfig to know your local IP address
• Now you are able to connect to the phone from another device with the following command: ssh root@<PHONE_IP_ADDRESS> -p 2222

Running node under Tor

Since you are using a mobile device you may use a SIM or an eSIM with a mobile data plan. In this case port forwarding to enable incoming connections to your node could not work due mobile operator limitations. Using Tor is the solution.

• If it is running stop Bitcoin Core (stop-btc command)
• If you didn't do it for a while run apt update
• Install tor running apt install tor
• Figure out where your torrc file is (/etc/tor/torrc is one possibility) and uncomment/add the following lines:

ControlPort 9051
CookieAuthentication 1
CookieAuthFileGroupReadable 1

• For further settings (i.e. anonymity) and more information about using Bitcoin Core with Tor you can follow the guide Setting up a Tor hidden service on Bitcoin Wiki
• Launch Tor with /etc/init.d/tor start (you can check if it is running with /etc/init.d/tor status)
• Start Bitcoin Core (with start-btc command) and then run debug-btc to take note of the Onion address that is advertised. You can check for reachability on BitNodes.io