update docs and check for invalid board names

README.md

@@ -115,12 +115,19 @@ Note: If you are building for an ARM Chromebook, you need the `qemu-user-static`
 #### I want to use a different Linux distribution. How can I do that?
 Using any Linux distro is possible, provided that you apply the [proper patches](https://github.com/ading2210/chromeos-systemd) to systemd and recompile it. Most distros have some sort of bootstrapping tool that allows you to install it to a directory on your host PC. Then, you can just pass that rootfs directory into `patch_rootfs.sh` and `build.sh`.
 
+Here is a list of distros that are supported out of the box:
+- Debian 12
+- Debian Unstable
+- Alpine Linux
+
+PRs to enable support for other distros are welcome. 
+
 Debian Sid (the rolling release version of Debian) is also supported if you just want newer packages, and you can install it by passing an argument to `build_complete.sh`: 
 ```bash
 sudo ./build_complete.sh dedede release=unstable
 ```
 
-There is also experimental support for Alpine Linux. The Alpine disk image is about half the size compared to Debian. Pass the `distro=alpine` to use it:
+There is also experimental support for Alpine Linux. The Alpine disk image is about half the size compared to Debian, although some applications are missing. Pass the `distro=alpine` to use it:
 ```bash
 sudo ./build_complete.sh dedede distro=alpine
 ```

build_complete.sh

@@ -14,7 +14,7 @@ print_help() {
   echo "  data_dir     - The working directory for the scripts. This defaults to ./data"
   echo "  arch         - The CPU architecture to build the shimboot image for. Set this to 'arm64' if you have an ARM Chromebook."
   echo "  release      - Set this to either 'bookworm' or 'unstable' to build for Debian stable/unstable."
-  echo "  distro       - The Linux distro to use. This should be either 'debian' or 'alpine'."
+  echo "  distro       - The Linux distro to use. This should be either 'debian', 'ubuntu', or 'alpine'."
 }
 
 assert_root
@@ -79,7 +79,12 @@ reco_url="$(wget -qO- --show-progress $boards_url | python3 -c '
 import json, sys
 
 all_builds = json.load(sys.stdin)
-board = all_builds["builds"][sys.argv[1]]
+board_name = sys.argv[1]
+if not board_name in all_builds["builds"]:
+  print("Invalid board name: " + board_name, file=sys.stderr)
+  sys.exit(1)
+  
+board = all_builds["builds"][board_name]
 if "models" in board:
   for device in board["models"].values():
     if device["pushRecoveries"]:
@@ -149,14 +154,26 @@ if [ ! "$rootfs_dir" ]; then
   if [ "$distro" = "debian" ]; then
     release="${release:-bookworm}"
   elif [ "$distro" = "ubuntu" ]; then
-    release="${release:-jammy}"
+    release="${release:-noble}"
   elif [ "$distro" = "alpine" ]; then
-    release="${release:-latest-stable}"
+    release="${release:-edge}"
   else
     print_error "invalid distro selection"
     exit 1
   fi
 
+  #install a newer debootstrap version if needed
+  if [ -f "/etc/debian_version" ] && [ "$distro" = "ubuntu" -o "$distro" = "debian" ]; then
+    if [ ! -f "/usr/share/debootstrap/scripts/$release" ]; then
+      print_info "installing newer debootstrap version"
+      mirror_url="https://deb.debian.org/debian/pool/main/d/debootstrap/"
+      deb_file="$(curl "https://deb.debian.org/debian/pool/main/d/debootstrap/" | pcregrep -o1 'href="(debootstrap_.+?\.deb)"' | tail -n1)"
+      deb_url="${mirror_url}${deb_file}"
+      wget -q --show-progress "$deb_url" -O "/tmp/$deb_file"
+      apt-get install -y "/tmp/$deb_file"
+    fi
+  fi
+
   ./build_rootfs.sh $rootfs_dir $release \
     custom_packages=$desktop_package \
     hostname=shimboot-$board \