iBotPeaches/Apktool · critical · AndrolibException

Unexpected chunk:

Error message

Unexpected chunk: 

What it means

BinaryResourceParser.parse expects the first chunk of a resources.arsc stream to be RES_TABLE_TYPE (the resource table root, type 0x0002). Any other leading chunk type throws this error, naming the chunk that was found instead.

Source

Thrown at brut.apktool/apktool-lib/src/main/java/brut/androlib/res/decoder/BinaryResourceParser.java:132

    public void enableCollectFlagsOffsets() {
        mEntrySpecFlagsOffsets = new ArrayList<>();
    }

    public Collection<Pair<Long, Integer>> getEntrySpecFlagsOffsets() {
        return mEntrySpecFlagsOffsets;
    }

    public void parse(InputStream in) throws AndrolibException {
        reset();
        mIn = new BinaryDataInputStream(new BufferedInputStream(in));

        ResChunkPullParser parser = new ResChunkPullParser(mIn);
        try {
            if (!nextChunk(parser)) {
                throw new AndrolibException("Input file is empty.");
            }
            if (parser.chunkType() != ResChunkHeader.RES_TABLE_TYPE) {
                throw new AndrolibException("Unexpected chunk: " + parser.chunkName() + " (expected: RES_TABLE_TYPE)");
            }

            parseTable(parser);

            Log.d(TAG, "End of chunks at 0x%08x", mIn.position());

            // We can't use remaining() here, the length of the main stream is unknown.
            if (mIn.available() > 0) {
                Log.d(TAG, "Ignoring trailing data at 0x%08x.", mIn.position());
            }
        } catch (IOException ex) {
            throw new AndrolibException("Could not decode arsc file.", ex);
        }
    }

    public void reset() {
        mIn = null;
        mMissingEntrySpecs.clear();

View on GitHub (pinned to 79b63384d7)

Solutions

1. Confirm the file is really resources.arsc: first two bytes (little-endian) should be 0x0002; a binary XML starts with 0x0003.
2. If parsing from a zip, make sure you opened the correct entry and that you are not passing a still-deflated stream (use ZipInputStream/ZipFile, not a raw FileInputStream on the APK).
3. Re-obtain the APK from a trusted source — obfuscators/packers that reorder chunks make the arsc undecodable by this parser.
4. Dump the first 16 bytes (`xxd resources.arsc | head -1`) and compare against the RES_TABLE_TYPE layout before debugging further.

Example fix

// before
try (InputStream in = zip.getInputStream(entry)) { parser.parse(in); }

// after
try (InputStream in = zip.getInputStream(entry)) {
    int lo = in.read(), hi = in.read();
    int chunkType = (hi << 8) | lo;
    if (chunkType != 0x0002) {
        throw new IllegalArgumentException("Not an arsc file: first chunk type 0x" + Integer.toHexString(chunkType));
    }
    parser.parse(new SequenceInputStream(new ByteArrayInputStream(new byte[]{(byte) lo, (byte) hi}), in));
}

byte[] head = new byte[2];
try (InputStream s = new FileInputStream(arscFile)) {
    if (s.read(head) != 2 || (head[0] & 0xFF) != 0x02 || head[1] != 0) {
        throw new IllegalArgumentException("Not a resources.arsc: bad first chunk type");
    }
}

try {
    parser.parse(in);
} catch (AndrolibException e) {
    if (e.getMessage().startsWith("Unexpected chunk:")) {
        // wrong file routed to arsc parser — check first bytes 0x0002
    }
}

When it happens

Trigger: Passing a non-arsc file to the arsc parser: a binary XML file (AXML), a DEX, or an arsc whose header bytes are corrupted/byte-swapped. Also happens when the stream was double-compressed and is being read while still deflated.

Common situations: Misrouted file in a custom pipeline (parsing AndroidManifest.xml or a .dex with the arsc parser); resources.arsc obfuscated by packers that shuffle chunk order; wrong stream opened from a zip entry; endian/encoding transforms applied by a repackaging tool.

Related errors

• Input file is empty.
• Config size < 8
• Could not decode arsc file.
• Missing type string pool.
• Missing key string pool

AI-assisted analysis of iBotPeaches/Apktool@79b63384d7 (2026-08-14). Data as JSON: /api/errors/81db24b85049ceae. Report an issue: GitHub.