Update readme

README.md

@@ -1,20 +1,42 @@
 # Beepberry Buildroot
 
-## Building an SD card image
+Buildroot is a slimmed-down, Beepy-centric image with a fast boot, compatible with the Raspberry Pi Zero 2 W. It is automatically set up with Beepy device drivers and a set of useful software. Tailored for on-the-go communication, it ships with the following applications:
 
-Run `./build-image.sh`. This will download Buildroot and build a Beepberry SD card image at `buildroot/output/images/sdcard.img`.
+* `gomuks` - Beeper command line client
+* `mosh` - Mobile remote shell
+* `w3m` - Text based browser
+* `aerc` - Command line email client
+* `nmtui` - Network management
+* Python 3 with `pip`
 
-For subsequent builds you can just run `make -j $(nproc)` from the `buildroot` directory.
+Please install [firmware version 3.4](https://github.com/ardangelo/beepberry-rp2040/releases/tag/v3.4) for this Buildroot release.
+
+## Pre-boot configuration: WiFi network and timezone
+
+After flashing the SD image, configuration files added to `/boot/wlan` will be copied to the IWD directory.
+
+You can rename and rename the file `/boot/wlan/ssid_goes_here.psk` to `/boot/wlan/<your_network_name>.psk` and edit its contents, replacing `passphrase_goes_here` with the network passphrase.
+
+After booting, You can use the `nmtui` utility to configure Wi-Fi.
 
-For the keyboard to work, you'll need to build and flash the firmware from this PR for now: https://github.com/sqfmi/i2c_puppet/pull/1
+The file `timezone.txt` on the SD card's boot partition can be edited to change the device timezone. When a network is connected, time will automatically synchronize with time servers.
 
-## Configuring a WiFi network
+## Usage
 
-After flashing the SD image, configuration files added to `/boot/wlan` will be copied to the IWD directory. Edit the default file to configure a connection.
+For keybindings and modifier key behaviors, see [`beepy-kbd` documentation](https://github.com/ardangelo/beepberry-keyboard-driver/blob/main/README.md).
 
+The initial boot will take about 30 seconds to resize disk partitions to fill your SD card. Subsequent boots take around 8 seconds from power-on to Tmux.
 
-## Extra: Connecting via SSH
+When a new Buildroot release is posted, you can update by reflashing the SD card, or by running the command `sudo update_buildroot` to pull the latest changes from the release image.
+
+## Connecting via SSH
 
 SSH is enabled by default, you can configure WiFi as above to connect remotely to debug.
 
 The username is `beepy` and the password is `beepbeep`. You should change this from the default using `passwd` as soon as possible for security reasons.
+
+## Building SD card image from source
+
+Run `./build-image.sh`. This will download Buildroot and build a Beepberry SD card image at `buildroot/output/images/sdcard.img`.
+
+For subsequent builds you can just run `make -j $(nproc)` from the `buildroot` directory.