seedsigner/docs/raspberry_pi_os_build_instructions.md

# Raspberry Pi OS Local Dev Build Instructions

Since v0.6.0, official releases use our custom [SeedSigner OS](https://github.com/SeedSigner/seedsigner-os/). However, project contributors looking to do rapid development cycles typically use the older Raspberry Pi OS that we had previously built on prior to v0.6.0. If you're here to set up your SeedSigner for local development, continue reading.

Begin by acquiring the latest 32-bit, Buster-based Raspberry Pi Lite operating system. This guide was tested using the version dated 2023-05-03, which can be found here:

https://downloads.raspberrypi.org/raspios_oldstable_lite_armhf/images/raspios_oldstable_lite_armhf-2023-05-03/

SeedSigner does not work with any of the more recent versions of Debian. This is a known limitation and there are open tickets to track the progress of this ([Debian 11 ticket](https://github.com/SeedSigner/seedsigner/issues/431), [Debian 12 ticket](https://github.com/SeedSigner/seedsigner/issues/430)). This guide does not work on the 64-bit versions of Buster, however pull requests to update it to be compatible are welcome.

Best practice is to verify the downloaded file containing the Raspberry Pi Lite OS matches the published SHA256 hash of the file; for additional reference that hash is: 3d210e61b057de4de90eadb46e28837585a9b24247c221998f5bead04f88624c. After verifying the file's data integrity, you can decompress the .tar.xz file to obtain the operating system image that it contains. You can then use Balena's Etcher tool (https://www.balena.io/etcher/) to write the Raspberry Pi Lite software image to a memory card (4 GB or larger). It's important to note that an image authoring tool must be used (the operating system image cannot be simply copied into a file storage partition on the memory card).

The manual SeedSigner installation and configuration process requires an internet connection on the Pi to download the necessary libraries and code.  
If your Pi does not have onboard WiFi, you have two options:

1. Run these steps on a separate Raspberry Pi 2/3/4 or Zero W which does have onboard WiFi to connect to the internet, and then move the SD card over to the non WiFi enabled Pi when complete.
2. OR configure the non WiFi enabled Pi directly by relaying through your computer's internet connection over USB. See instructions [here](usb_relay.md).

If your Pi does have onboard WiFi, then using the Raspberry Pi Imager software will allow you to easily configure your Pi's WiFi connection, as well as simultaneously write the image file. That will make your initial SSH into the Pi much easier.   
Use the Pi's onboard WiFi only if you are setting up a local development environment, never for real funds or binary image creation. 
  
For the following steps you'll need to either connect a keyboard & monitor to the network-connected Raspberry Pi you are working with, or SSH into the Pi if you're familiar with that process.

### Configure the Pi
First things first, verify that you are using the correct version of the Raspberry Pi Lite operating system by typing the command:
```bash
cat /etc/os-release
```

The output of this command should match the following text:
```bash
PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"
```

Now launch the Raspberry Pi's System Configuration tool using the command:
```bash
sudo raspi-config
```

Set the following:
* `Interface Options`:
    * `Camera`: enable
    * `SPI`: enable
* `Localisation Options`:
    * `Locale`: arrow up and down through the list and select or deselect languages with the spacebar.
        * Deselect the default language option that is selected
        * Select `en_US.UTF-8 UTF-8` for US English
        * Use the `TAB` button to select `Ok` and press `ENTER`
        * On the next screen select `en_US.UTF-8` for the default locale
* You will also need to configure the WiFi settings if you are using the #1 option above to connect to the internet

When you exit the System Configuration tool, you will be prompted to reboot the system; allow the system to reboot and continue with these instructions.

Each command should be run individually, unless it's specified as a multi-line command.
### Change the default password
Change the system's default password from the default "raspberry". Run the command:
```bash
passwd
```
You will be prompted to enter the current password ("raspberry") and then to enter a new password twice. In our prepared release image, the password used is `AirG@pped!`.

### Install python3.10
```bash
# install compiler dependencies; takes ~1 minute on a Pi Zero 1.3
# * openssl, libssl-dev: ssl support when pip fetches packages
# * libsqlite3-dev: required by `coverage`
sudo apt update && sudo apt install -y build-essential zlib1g-dev \
    libncurses5-dev libgdbm-dev libnss3-dev openssl libssl-dev \
    libreadline-dev libffi-dev wget libsqlite3-dev

# Grab the python3.10 source
wget https://www.python.org/ftp/python/3.10.10/Python-3.10.10.tgz
tar -xzvf Python-3.10.10.tgz
cd Python-3.10.10

# Takes ~6 minutes on a Pi Zero 1.3 to check what is available
./configure --enable-optimizations

# compiling takes ~80 minutes(!!) on a Pi Zero 1.3
sudo make altinstall

# cleanup
cd ..
sudo rm -rf Python-3.10.10*

# Make python3.10 the default version
sudo update-alternatives --install /usr/bin/python python /usr/local/bin/python3.10 1
sudo update-alternatives --install /usr/bin/python3 python3 /usr/local/bin/python3.10 1
```

Manually re-install `python3-apt` to avoid error messages in later steps (though, ironically, you will see the "ModuleNotFoundError: No module named 'apt_pkg'" error message during the `apt remove` step):
```bash
sudo apt remove --purge python3-apt -y
sudo apt autoremove -y
sudo apt install python3-apt -y
```

### Install dependencies
Copy this entire box and run it as one command (~15 minutes on a Pi Zero 1.3):
```bash
sudo apt update && sudo apt install -y wiringpi python3-pip \
   python-pil libjpeg-dev zlib1g-dev libopenjp2-7 \
   git python3-opencv python3-picamera libatlas-base-dev qrencode
```

### Install `zbar`
`zbar` is "an open source software suite for reading bar codes" (more info here: [https://github.com/mchehab/zbar](https://github.com/mchehab/zbar)).

SeedSigner requires `zbar` at 0.23.x or higher.

Download the binary:
```bash
curl -L http://raspbian.raspberrypi.org/raspbian/pool/main/z/zbar/libzbar0_0.23.90-1+deb11u1_armhf.deb --output libzbar0_0.23.90-1_armhf.deb
```

And then install it:
```bash
sudo apt install ./libzbar0_0.23.90-1_armhf.deb
```

Cleanup:
```bash
rm libzbar0_0.23.90-1_armhf.deb
```

### Install the [C library for Broadcom BCM 2835](http://www.airspayce.com/mikem/bcm2835/)
This library "provides functions for reading digital inputs and setting digital outputs, using SPI and I2C, and for accessing the system timers."

Run each of the following individual steps:
```bash
wget http://www.airspayce.com/mikem/bcm2835/bcm2835-1.60.tar.gz
tar zxvf bcm2835-1.60.tar.gz
cd bcm2835-1.60/
sudo ./configure
sudo make && sudo make check && sudo make install
cd ..
rm bcm2835-1.60.tar.gz
sudo rm -rf bcm2835-1.60
```

### Download the SeedSigner code:
```bash
git clone https://github.com/SeedSigner/seedsigner
cd seedsigner
```

### Adding swap space
Compiling the dependencies requires more RAM than is available on a Raspberry
Pi 3B, let alone a Zero. Temporarily adding 1GB of additional swap space will
work around this limitation. The `/swapfile` can be deleted after you reboot.

If building on a Raspberry Pi board with more than 1GB of RAM, this step can
be safely skipped.

```bash
sudo dd if=/dev/zero of=/swapfile bs=4096 count=$((1024*256))
sudo chmod 0600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
```

### Install Python `pip` dependencies:
```bash
# Takes 1hr 15min on a Pi Zero 1.3
python3 -m pip install -r requirements.txt

# Only takes ~100 seconds
python3 -m pip install -r requirements-raspi.txt
```

#### `pyzbar`
Note: The `requirements.txt` installs a fork of the python `pyzbar` repo.

The fork is required because the main `pyzbar` repo has been abandoned. This [github issue](https://github.com/NaturalHistoryMuseum/pyzbar/issues/124#issuecomment-971967091) discusses the changes needed in order to support reading binary data from `zbar`, which is required for our `CompactSeedQR` format which writes byte data instead of strings. The changes specifically reference the following PRs which have already been merged into Keith's fork:
* [PR 76](https://github.com/NaturalHistoryMuseum/pyzbar/pull/76/files): enables scanning to continue even when a null byte (`x\00`) is found.
* [PR 82](https://github.com/NaturalHistoryMuseum/pyzbar/pull/82): enable `zbar`'s new binary mode. Note that this PR has a trivial bug that was fixed in our fork.


### Optional: increase spidev buffer size
This allows `ST7789.py` to update the LCD without performing multiple write operations because the default buffer size is 4096 bytes. The default can be changed via the `/boot/cmdline.txt` file. You will need to add `spidev.bufsiz=131072` to the end of this single lined file command.

Example `cmdline.txt` contents:
```
console=serial0,115200 console=tty1 root=PARTUUID=2fa4ba7e-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait modules-load=dwc2,g_ether spidev.bufsiz=131072
```

### Configure `systemd` to run SeedSigner at boot:

```bash
sudo nano /etc/systemd/system/seedsigner.service
```

Add the following contents to the text file that was created:  
If you are not using the username pi, then replace `pi` in the service section below with your username. There are 3 lines to change.   
```ini
[Unit]
Description=Seedsigner

[Service]
User=pi
WorkingDirectory=/home/pi/seedsigner/src/
ExecStart=/usr/bin/python3 main.py
StandardOutput=null
ErrorOutput=null
Restart=always

[Install]
WantedBy=multi-user.target
```

_Note: For local dev you'll want to edit the `Restart=always` line to `Restart=no`. This way when your dev code crashes it won't keep trying to restart itself. Note that the UI "Reset" will no longer work when auto-restarts are disabled._

_Note: Debugging output is completely wiped via routing the stdout and stderr to `/dev/null`. When working in local dev, you'll `kill` the `systemd` SeedSigner service and just directly run the code on demand so you can see all the debugging output live._

Use `CTRL-X` and `y` to exit and save changes.

Configure the service to start running (this will restart the seedsigner code automatically at startup and if it crashes):
```bash
sudo systemctl enable seedsigner.service
```

Now reboot the Raspberry Pi:
```bash
sudo reboot
```

After the Raspberry Pi reboots, you should see the SeedSigner splash screen and the SeedSigner menu subsequently appear on the LCD screen (note that it can take up to 60 seconds for the menu to appear).


#### Optional: kill `systemd` SeedSigner process on login
If you're going to be testing new code on the device, you'll find yourself often needing to kill the SeedSigner instance that `systemd` automatically runs at startup.

You can configure your `~/.profile` to find and kill the SeedSigner process when you ssh in.

`nano ~/.profile` and add at the end:
```bash
# Find the SeedSigner process and kill it
kill $(ps aux | grep '[m]ain.py' | awk '{print $2}')
```


### Further OS modifications
Disable and remove the system's virtual memory / swap file with the commands:

```bash
sudo apt remove dphys-swapfile -y
sudo apt autoremove -y
sudo rm /var/swap
```

## Manually start the SeedSigner code
```bash
cd ~/seedsigner/src

# You'll find the main.py file in that directory. Run it:
python main.py

# To kill the process, use CTRL-C
```


## Local testing and development

### Run specific branches or PRs
The default branch is `dev`. If you want to run a specific release tag or a specific branch:
```bash
# release tag for v0.6.0:
git checkout 0.6.0
```

And if you want to test a pull request (PR), for example PR #123:
```bash
git fetch origin pull/123/head:pr_123
git checkout pr_123
```

where `pr_123` is any name you want to give to the new branch in your local repo that will hold the PR.


### Change the host name
For those who will use the SeedSigner installation for testing/development, it can be helpful to change the system's host name so it doesn't potentially conflict with other Raspberry Pis that may already be present on your network. (For those who don't plan to use the installation for testing or development, you can skip this portion of the process.) To change the host name first edit the "hostname" with the command:

```bash
sudo nano /etc/hostname
```

and change "raspberrypi" to "seedsigner" (or another name). Use `CTRL-X` and `y` to exit and save changes.

You'll also need to edit the "hosts" file with the command:
```bash
sudo nano /etc/hosts
```

and change "raspberrypi" to "seedsigner" (or the other name you previously chose). Use `CTRL-X` and `y` to exit and save changes.

### Set a static IP
Your local machine that `ssh`s into the SeedSigner can sometimes get confused if you're connecting to different SeedSigners that are all identified as `pi@seedsigner.local`. In this case it helps to set a static ip and just `ssh` directly to that instead.

First find your current `nameserver`:
```bash
sudo cat /etc/resolv.conf
```

This is the address of your local machine that is connected to your SeedSigner via USB (or it'll be the WiFi router's address if you're using a Raspberry Pi with WiFi and are keeping it enabled for `ssh` access).

Set a static IP: `sudo nano /etc/dhcpcd.conf` and add to the end:
```
interface usb0
static ip_address=192.168.1.200/24
static routers=192.168.1.254
static domain_name_servers=192.168.1.254
```

* `interface` will be `usb0` for USB connections; `wlan0` for WiFi.
* `static ip_address` is the IP address you want the SeedSigner to use. It should match the `nameserver` IP you found above for all but the last part of the IP (note: the `/24` should always be included as-is).
* `static routers` should be your `nameserver` IP.
* `static domain_name_servers` should also be the `nameserver` IP.

`CTRL-X` and `y` to save changes.

After your next reboot, access this SeedSigner using its new static IP:
```bash
# Use the static IP you set above:
ssh pi@192.168.1.200

# But the hostname will still work, too:
ssh pi@seedsigner.local
```

### More convenient `ssh` access:
Power SeedSigner devs will find themselves connecting to a lot of different SeedSigners. This can cause headaches with `ssh`'s built-in protections; a different device that uses the same `ssh` credentials is normally a potential spoofing attack. But we're doing this to ourselves on purpose and so we can carve out exceptions.

On your local machine, run `nano ~/.ssh/config` and add to the end:
```conf
host seedsigner.local
 StrictHostKeyChecking no
 UserKnownHostsFile /dev/null
 User pi
 LogLevel QUIET

# Set this to the static IP you set above:
host 192.168.1.200
 StrictHostKeyChecking no
 UserKnownHostsFile /dev/null
 User pi
 LogLevel QUIET
```

The first entry prevents warnings for the default `pi@seedsigner.local` connections.

The second entry does the same for a specific static IP; you'll want this if you configure all your SeedSigners to use the same static IP.

`CTRL-X` and `y` to save changes.


#### Bypass `ssh` password
You can also configure the SeedSigner so that you don't have to enter the `pi` password when you `ssh` in.

run `ssh-copy-id` with the same values that you connect via `ssh`:
```bash
ssh-copy-id pi@seedsigner.local

# or if you're connecting over static IP, something like:
ssh-copy-id pi@192.168.1.200
```

You'll be prompted to enter the password to complete it.

_Note: If you don't have any ssh keys on your local machine, you'll need to create a set with `ssh-keygen -t ed25519 -C "your_email@example.com"`. Then try running `ssh-copy-id` again._


## Disable WiFi/Bluetooth when using other Raspberry Pi boards
If you plan to use your installation on a Raspberry Pi that is not a Zero version 1.3, but rather on a Raspberry Pi that has WiFi and Bluetooth capabilities, it is a good idea to disable the following WiFi & Bluetooth, as well as other relevant services (assuming you are not creating this installation for testing/development purposes). Enter the following commands to disable WiFi, Bluetooth, & other relevant services:
```bash
sudo systemctl disable bluetooth.service
sudo systemctl disable wpa_supplicant.service
sudo systemctl disable dhcpcd.service
sudo systemctl disable sshd.service
sudo systemctl disable networking.service
sudo systemctl disable dphys-swapfile.service
sudo ifconfig wlan0 down
```

Please note that if you are using WiFi to connect/interact with your Raspberry Pi, the last command will sever that connection.

You can now safely power the Raspberry Pi off from the SeedSigner main menu.

If you do not plan to use your installation for testing/development, it is also a good idea to disable WiFi and Bluetooth by editing the config.txt file found in the installation's "boot" partition. You can add the following text to the end of that file with any simple text editor (Windows: Notepad, Mac: TextEdit, Linux: nano):
```ini
dtoverlay=disable-bt
dtoverlay=pi3-disable-wifi
```

If you used option #2 above and don't plan to continue to access your SeedSigner via SSH over USB, it is a good idea to reverse the steps you took to enable it -- those instructions can be found near the end of [this guide](usb_relay.md).

Please remember that it can take up to a minute for the GUI to appear when powering your SeedSigner on.


### Optional: Run the tests
see: [tests/README.md](../tests/README.md)