fix minor bugs in build script

README.md

@@ -77,12 +77,11 @@ PRs and contributions are welcome to help implement these features.
   - Github Codespaces is not supported at the moment
 - A USB drive that is at least 8GB in size
 - At least 20GB of free disk space
-- An x86-based Chromebook
 
 ### Build Instructions:
 1. Find the board name of your Chromebook. You can search for the model name on [chrome100.dev](https://chrome100.dev/).
 1. Clone this repository and cd into it.
-2. Run `sudo ./build_complete.sh <board_name>` to download the required data and build the disk image.
+2. Run `sudo ./build_complete.sh <board_name>` to download the required data and build the disk image. If you have an ARM-based Chromebook, pass `arch=arm64` in as an option.
 
 Alternatively, you can run each of the steps manually:
 1. Grab a Chrome OS RMA Shim from somewhere. Most of them have already been leaked and aren't too difficult to find.

build_complete.sh

@@ -26,7 +26,7 @@ desktop="${args['desktop']-'xfce'}"
 data_dir="${args['data_dir']}"
 arch="${args['arch']-'amd64'}"
 
-needed_deps="wget python3 unzip zip git debootstrap cpio binwalk pcregrep cgpt mkfs.ext4 mkfs.ext2 fdisk rsync depmod findmnt"
+needed_deps="wget python3 unzip zip git debootstrap cpio binwalk pcregrep cgpt mkfs.ext4 mkfs.ext2 fdisk rsync depmod findmnt lz4"
 if [ "$(check_deps "$needed_deps")" ]; then
   #install deps automatically on debian and ubuntu
   if [ -f "/etc/debian_version" ]; then

shim_utils.sh

@@ -32,7 +32,7 @@ extract_initramfs_arm() {
 
   #extract the kernel lz4 archive from the partition
   local binwalk_out="$(binwalk $kernel_bin --run-as=root)"
-  local lz4_offset="$(echo "$binwalk_out" | pcregrep -o1 "(\d+).+?LZ4 compressed data")"
+  local lz4_offset="$(echo "$binwalk_out" | pcregrep -o1 "(\d+).+?LZ4 compressed data" | head -n1)"
   local lz4_file="$working_dir/kernel.lz4"
   local kernel_img="$working_dir/kernel_decompressed.bin"
   dd if=$kernel_bin of=$lz4_file iflag=skip_bytes,count_bytes skip=$lz4_offset