ASUS Fugu bootloader.img format (version 2 and later): Java parsing library

A bootloader image which only seems to have been used on a few ASUS devices. The encoding is ASCII, because the releasetools.py script is written using Python 2, where the default encoding is ASCII.

A test file can be found in the firmware files for the "fugu" device, which can be downloaded from https://developers.google.com/android/images

File extension

img

KS implementation details

License: CC0-1.0
Minimal Kaitai Struct required: 0.9

This page hosts a formal specification of ASUS Fugu bootloader.img format (version 2 and later) using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Java generated by Kaitai Struct depends on the Java runtime library. You have to install it before you can parse data.

The Java runtime library is published in the Maven Central Repository. Refer to the artifact page for instructions how to add it into your project with the build tool that you use.

Code

Parse a local file and get structure in memory:

AndroidBootldrAsus data = AndroidBootldrAsus.fromFile("path/to/local/file.img");

Or parse structure from a byte array:

byte[] someArray = new byte[] { ... };
AndroidBootldrAsus data = new AndroidBootldrAsus(new ByteBufferKaitaiStream(someArray));

After that, one can get various attributes from the structure by invoking getter methods like:

data.images() // => Only three images are included: `ifwi.bin`, `droidboot.img`
and `splashscreen.img`

Java source code to parse ASUS Fugu bootloader.img format (version 2 and later)

AndroidBootldrAsus.java

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

import io.kaitai.struct.ByteBufferKaitaiStream;
import io.kaitai.struct.KaitaiStruct;
import io.kaitai.struct.KaitaiStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.ArrayList;
import java.nio.charset.Charset;


/**
 * A bootloader image which only seems to have been used on a few ASUS
 * devices. The encoding is ASCII, because the `releasetools.py` script
 * is written using Python 2, where the default encoding is ASCII.
 * 
 * A test file can be found in the firmware files for the "fugu" device,
 * which can be downloaded from <https://developers.google.com/android/images>
 * @see <a href="https://android.googlesource.com/device/asus/fugu/+/android-8.1.0_r5/releasetools.py">Source</a>
 */
public class AndroidBootldrAsus extends KaitaiStruct {
    public static AndroidBootldrAsus fromFile(String fileName) throws IOException {
        return new AndroidBootldrAsus(new ByteBufferKaitaiStream(fileName));
    }

    public AndroidBootldrAsus(KaitaiStream _io) {
        this(_io, null, null);
    }

    public AndroidBootldrAsus(KaitaiStream _io, KaitaiStruct _parent) {
        this(_io, _parent, null);
    }

    public AndroidBootldrAsus(KaitaiStream _io, KaitaiStruct _parent, AndroidBootldrAsus _root) {
        super(_io);
        this._parent = _parent;
        this._root = _root == null ? this : _root;
        _read();
    }
    private void _read() {
        this.magic = this._io.readBytes(8);
        if (!(Arrays.equals(magic(), new byte[] { 66, 79, 79, 84, 76, 68, 82, 33 }))) {
            throw new KaitaiStream.ValidationNotEqualError(new byte[] { 66, 79, 79, 84, 76, 68, 82, 33 }, magic(), _io(), "/seq/0");
        }
        this.revision = this._io.readU2le();
        if (!(revision() >= 2)) {
            throw new KaitaiStream.ValidationLessThanError(2, revision(), _io(), "/seq/1");
        }
        this.reserved1 = this._io.readU2le();
        this.reserved2 = this._io.readU4le();
        images = new ArrayList<Image>(((Number) (3)).intValue());
        for (int i = 0; i < 3; i++) {
            this.images.add(new Image(this._io, this, _root));
        }
    }
    public static class Image extends KaitaiStruct {
        public static Image fromFile(String fileName) throws IOException {
            return new Image(new ByteBufferKaitaiStream(fileName));
        }

        public Image(KaitaiStream _io) {
            this(_io, null, null);
        }

        public Image(KaitaiStream _io, AndroidBootldrAsus _parent) {
            this(_io, _parent, null);
        }

        public Image(KaitaiStream _io, AndroidBootldrAsus _parent, AndroidBootldrAsus _root) {
            super(_io);
            this._parent = _parent;
            this._root = _root;
            _read();
        }
        private void _read() {
            this.chunkId = new String(this._io.readBytes(8), Charset.forName("ASCII"));
            if (!( ((chunkId().equals("IFWI!!!!")) || (chunkId().equals("DROIDBT!")) || (chunkId().equals("SPLASHS!"))) )) {
                throw new KaitaiStream.ValidationNotAnyOfError(chunkId(), _io(), "/types/image/seq/0");
            }
            this.lenBody = this._io.readU4le();
            this.flags = this._io.readU1();
            {
                int _it = flags();
                if (!((_it & 1) != 0)) {
                    throw new KaitaiStream.ValidationExprError(flags(), _io(), "/types/image/seq/2");
                }
            }
            this.reserved1 = this._io.readU1();
            this.reserved2 = this._io.readU1();
            this.reserved3 = this._io.readU1();
            this.body = this._io.readBytes(lenBody());
        }
        private String fileName;
        public String fileName() {
            if (this.fileName != null)
                return this.fileName;
            this.fileName = (chunkId().equals("IFWI!!!!") ? "ifwi.bin" : (chunkId().equals("DROIDBT!") ? "droidboot.img" : (chunkId().equals("SPLASHS!") ? "splashscreen.img" : "")));
            return this.fileName;
        }
        private String chunkId;
        private long lenBody;
        private int flags;
        private int reserved1;
        private int reserved2;
        private int reserved3;
        private byte[] body;
        private AndroidBootldrAsus _root;
        private AndroidBootldrAsus _parent;
        public String chunkId() { return chunkId; }
        public long lenBody() { return lenBody; }
        public int flags() { return flags; }
        public int reserved1() { return reserved1; }
        public int reserved2() { return reserved2; }
        public int reserved3() { return reserved3; }
        public byte[] body() { return body; }
        public AndroidBootldrAsus _root() { return _root; }
        public AndroidBootldrAsus _parent() { return _parent; }
    }
    private byte[] magic;
    private int revision;
    private int reserved1;
    private long reserved2;
    private ArrayList<Image> images;
    private AndroidBootldrAsus _root;
    private KaitaiStruct _parent;
    public byte[] magic() { return magic; }
    public int revision() { return revision; }
    public int reserved1() { return reserved1; }
    public long reserved2() { return reserved2; }

    /**
     * Only three images are included: `ifwi.bin`, `droidboot.img`
     * and `splashscreen.img`
     */
    public ArrayList<Image> images() { return images; }
    public AndroidBootldrAsus _root() { return _root; }
    public KaitaiStruct _parent() { return _parent; }
}