README.md: add documentation of live iso kcl vars

also change the heading levels to make more sense

README.md

@@ -1,4 +1,4 @@
-## The Void Linux image/live/rootfs maker and installer
+# The Void Linux image/live/rootfs maker and installer
 
 This repository contains utilities for Void Linux:
 
@@ -10,16 +10,16 @@ This repository contains utilities for Void Linux:
  * mkrootfs  (The Void Linux rootfs maker for ARM platforms)
  * mknet (Script to generate netboot tarballs for Void)
 
-#### Build Dependencies
+## Build Dependencies
  * make
 
-#### Dependencies
+## Dependencies
  * Compression type for the initramfs image
    * liblz4 (for lz4, xz) (default)
  * xbps>=0.45
  * qemu-user-static binaries (for mkrootfs)
 
-#### Usage
+## Usage
 
 Type
 
@@ -31,7 +31,7 @@ and then see the usage output:
     $ ./mkrootfs.sh -h
     $ ./mkimage.sh -h
 
-#### Examples
+### Examples
 
 Build a native live image keyboard set to 'fr':
 
@@ -46,3 +46,23 @@ Build an x86\_64 musl live image with packages stored in a local repository:
     # ./mklive.sh -a x86_64-musl -r /path/to/host/binpkgs
 
 See the usage output for more information :-)
+
+## Kernel Command-line Parameters
+
+`void-mklive`-based live images support several kernel command-line arguments
+that can change the behavior of the live system:
+
+- `live.autologin` will skip the initial login screen on `tty1`.
+- `live.user` will change the username of the non-root user from the default `anon`. The password remains `voidlinux`.
+- `live.shell` sets the default shell for the non-root user in the live environment.
+- `live.screenreader` enables the console screenreader `espeakup` in the live environment.
+- `console` can be set to `ttyS0`, `hvc0`, or `hvsi0` to enable `agetty` on that serial console.
+- `locale.LANG` will set the `LANG` environment variable. Defaults to `en_US.UTF-8`.
+- `vconsole.keymap` will set the console keymap. Defaults to `us`.
+
+### Examples:
+
+- `live.autologin live.user=foo live.shell=/bin/bash` would create the user `foo` with the default shell `/bin/bash` on boot, and log them in automatically on `tty1`
+- `live.shell=/bin/bash` would set the default shell for the `anon` user to `/bin/bash`
+- `console=ttyS0 vconsole.keymap=cf` would enable `ttyS0` and set the keymap in the console to `cf`
+- `locale.LANG=fr_CA.UTF-8` would set the live system's language to `fr_CA.UTF-8`