Qualcomm Snapdragon (MSM) bootloader.img format: Go parsing library

A bootloader for Android used on various devices powered by Qualcomm Snapdragon chips:

https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors

Although not all of the Snapdragon based Android devices use this particular bootloader format, it is known that devices with the following chips have used it (example devices are given for each chip):

(*) bootloader_size is equal to the size of the whole file (not just img_bodies as usual).

(**) There are some data after the end of img_bodies.


On the other hand, devices with these chips do not use this format:


The bootloader-*.img samples referenced above originally come from factory images packed in ZIP archives that can be found on the page Factory Images for Nexus and Pixel Devices on the Google Developers site. Note that the codenames on that page may be different than the ones that are written in the list above. That's because the Google page indicates ROM codenames in headings (e.g. "occam" for Nexus 4) but the above list uses model codenames (e.g. "mako" for Nexus 4) because that is how the original bootloader-*.img files are identified. For most devices, however, these code names are the same.

File extension

img

KS implementation details

License: CC0-1.0

This page hosts a formal specification of Qualcomm Snapdragon (MSM) bootloader.img format using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Go source code to parse Qualcomm Snapdragon (MSM) bootloader.img format

android_bootldr_qcom.go

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

import (
	"github.com/kaitai-io/kaitai_struct_go_runtime/kaitai"
	"bytes"
	"io"
)


/**
 * A bootloader for Android used on various devices powered by Qualcomm
 * Snapdragon chips:
 * 
 * <https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors>
 * 
 * Although not all of the Snapdragon based Android devices use this particular
 * bootloader format, it is known that devices with the following chips have used
 * it (example devices are given for each chip):
 * 
 * * APQ8064 ([devices](https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors#Snapdragon_S4_Pro))
 *   - Nexus 4 "mako": [sample][sample-mako] ([other samples][others-mako]),
 *     [releasetools.py](https://android.googlesource.com/device/lge/mako/+/33f0114/releasetools.py#98)
 * 
 * * MSM8974AA ([devices](https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors#Snapdragon_800,_801_and_805_(2013/14)))
 *   - Nexus 5 "hammerhead": [sample][sample-hammerhead] ([other samples][others-hammerhead]),
 *     [releasetools.py](https://android.googlesource.com/device/lge/hammerhead/+/7618a7d/releasetools.py#116)
 * 
 * * MSM8992 ([devices](https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors#Snapdragon_808_and_810_(2015)))
 *   - Nexus 5X "bullhead": [sample][sample-bullhead] ([other samples][others-bullhead]),
 *     [releasetools.py](https://android.googlesource.com/device/lge/bullhead/+/2994b6b/releasetools.py#126)
 * 
 * * APQ8064-1AA ([devices](https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors#Snapdragon_600_(2013)))
 *   - Nexus 7 \[2013] (Mobile) "deb" <a href="#doc-note-data-after-img-bodies">(\**)</a>: [sample][sample-deb] ([other samples][others-deb]),
 *     [releasetools.py](https://android.googlesource.com/device/asus/deb/+/14c1638/releasetools.py#105)
 *   - Nexus 7 \[2013] (Wi-Fi) "flo" <a href="#doc-note-data-after-img-bodies">(\**)</a>: [sample][sample-flo] ([other samples][others-flo]),
 *     [releasetools.py](https://android.googlesource.com/device/asus/flo/+/9d9fee9/releasetools.py#130)
 * 
 * * MSM8996 Pro-AB ([devices](https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors#Snapdragon_820_and_821_(2016)))
 *   - Pixel "sailfish" <a href="#doc-note-bootloader-size">(\*)</a>:
 *     [sample][sample-sailfish] ([other samples][others-sailfish])
 *   - Pixel XL "marlin" <a href="#doc-note-bootloader-size">(\*)</a>:
 *     [sample][sample-marlin] ([other samples][others-marlin])
 * 
 * * MSM8998 ([devices](https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors#Snapdragon_835_(2017)))
 *   - Pixel 2 "walleye" <a href="#doc-note-bootloader-size">(\*)</a>: [sample][sample-walleye] ([other samples][others-walleye])
 *   - Pixel 2 XL "taimen": [sample][sample-taimen] ([other samples][others-taimen])
 * 
 * <small id="doc-note-bootloader-size">(\*)
 * `bootloader_size` is equal to the size of the whole file (not just `img_bodies` as usual).
 * </small>
 * 
 * <small id="doc-note-data-after-img-bodies">(\**)
 * There are some data after the end of `img_bodies`.
 * </small>
 * 
 * ---
 * 
 * On the other hand, devices with these chips **do not** use this format:
 * 
 * * <del>APQ8084</del> ([devices](https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors#Snapdragon_800,_801_and_805_(2013/14)))
 *   - Nexus 6 "shamu": [sample][foreign-sample-shamu] ([other samples][foreign-others-shamu]),
 *     [releasetools.py](https://android.googlesource.com/device/moto/shamu/+/df9354d/releasetools.py#12) -
 *     uses "Motoboot packed image format" instead
 * 
 * * <del>MSM8994</del> ([devices](https://en.wikipedia.org/wiki/Devices_using_Qualcomm_Snapdragon_processors#Snapdragon_808_and_810_(2015)))
 *   - Nexus 6P "angler": [sample][foreign-sample-angler] ([other samples][foreign-others-angler]),
 *     [releasetools.py](https://android.googlesource.com/device/huawei/angler/+/cf92cd8/releasetools.py#29) -
 *     uses "Huawei Bootloader packed image format" instead
 * 
 * [sample-mako]: https://androidfilehost.com/?fid=96039337900113996 "bootloader-mako-makoz30f.img"
 * [others-mako]: https://androidfilehost.com/?w=search&s=bootloader-mako&type=files
 * 
 * [sample-hammerhead]: https://androidfilehost.com/?fid=385035244224410247 "bootloader-hammerhead-hhz20h.img"
 * [others-hammerhead]: https://androidfilehost.com/?w=search&s=bootloader-hammerhead&type=files
 * 
 * [sample-bullhead]: https://androidfilehost.com/?fid=11410963190603870177 "bootloader-bullhead-bhz32c.img"
 * [others-bullhead]: https://androidfilehost.com/?w=search&s=bootloader-bullhead&type=files
 * 
 * [sample-deb]: https://androidfilehost.com/?fid=23501681358552487 "bootloader-deb-flo-04.02.img"
 * [others-deb]: https://androidfilehost.com/?w=search&s=bootloader-deb-flo&type=files
 * 
 * [sample-flo]: https://androidfilehost.com/?fid=23991606952593542 "bootloader-flo-flo-04.05.img"
 * [others-flo]: https://androidfilehost.com/?w=search&s=bootloader-flo-flo&type=files
 * 
 * [sample-sailfish]: https://androidfilehost.com/?fid=6006931924117907154 "bootloader-sailfish-8996-012001-1904111134.img"
 * [others-sailfish]: https://androidfilehost.com/?w=search&s=bootloader-sailfish&type=files
 * 
 * [sample-marlin]: https://androidfilehost.com/?fid=6006931924117907131 "bootloader-marlin-8996-012001-1904111134.img"
 * [others-marlin]: https://androidfilehost.com/?w=search&s=bootloader-marlin&type=files
 * 
 * [sample-walleye]: https://androidfilehost.com/?fid=14943124697586348540 "bootloader-walleye-mw8998-003.0085.00.img"
 * [others-walleye]: https://androidfilehost.com/?w=search&s=bootloader-walleye&type=files
 * 
 * [sample-taimen]: https://androidfilehost.com/?fid=14943124697586348536 "bootloader-taimen-tmz30m.img"
 * [others-taimen]: https://androidfilehost.com/?w=search&s=bootloader-taimen&type=files
 * 
 * [foreign-sample-shamu]: https://androidfilehost.com/?fid=745849072291678307 "bootloader-shamu-moto-apq8084-72.04.img"
 * [foreign-others-shamu]: https://androidfilehost.com/?w=search&s=bootloader-shamu&type=files
 * 
 * [foreign-sample-angler]: https://androidfilehost.com/?fid=11410963190603870158 "bootloader-angler-angler-03.84.img"
 * [foreign-others-angler]: https://androidfilehost.com/?w=search&s=bootloader-angler&type=files
 * 
 * ---
 * 
 * The `bootloader-*.img` samples referenced above originally come from factory
 * images packed in ZIP archives that can be found on the page [Factory Images
 * for Nexus and Pixel Devices](https://developers.google.com/android/images) on
 * the Google Developers site. Note that the codenames on that page may be
 * different than the ones that are written in the list above. That's because the
 * Google page indicates **ROM codenames** in headings (e.g. "occam" for Nexus 4)
 * but the above list uses **model codenames** (e.g. "mako" for Nexus 4) because
 * that is how the original `bootloader-*.img` files are identified. For most
 * devices, however, these code names are the same.
 * @see <a href="https://android.googlesource.com/device/lge/hammerhead/+/7618a7d/releasetools.py">Source</a>
 */
type AndroidBootldrQcom struct {
	Magic []byte
	NumImages uint32
	OfsImgBodies uint32
	BootloaderSize uint32
	ImgHeaders []*AndroidBootldrQcom_ImgHeader
	_io *kaitai.Stream
	_root *AndroidBootldrQcom
	_parent interface{}
	_f_imgBodies bool
	imgBodies []*AndroidBootldrQcom_ImgBody
}
func NewAndroidBootldrQcom() *AndroidBootldrQcom {
	return &AndroidBootldrQcom{
	}
}

func (this *AndroidBootldrQcom) Read(io *kaitai.Stream, parent interface{}, root *AndroidBootldrQcom) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp1, err := this._io.ReadBytes(int(8))
	if err != nil {
		return err
	}
	tmp1 = tmp1
	this.Magic = tmp1
	if !(bytes.Equal(this.Magic, []uint8{66, 79, 79, 84, 76, 68, 82, 33})) {
		return kaitai.NewValidationNotEqualError([]uint8{66, 79, 79, 84, 76, 68, 82, 33}, this.Magic, this._io, "/seq/0")
	}
	tmp2, err := this._io.ReadU4le()
	if err != nil {
		return err
	}
	this.NumImages = uint32(tmp2)
	tmp3, err := this._io.ReadU4le()
	if err != nil {
		return err
	}
	this.OfsImgBodies = uint32(tmp3)
	tmp4, err := this._io.ReadU4le()
	if err != nil {
		return err
	}
	this.BootloaderSize = uint32(tmp4)
	this.ImgHeaders = make([]*AndroidBootldrQcom_ImgHeader, this.NumImages)
	for i := range this.ImgHeaders {
		tmp5 := NewAndroidBootldrQcom_ImgHeader()
		err = tmp5.Read(this._io, this, this._root)
		if err != nil {
			return err
		}
		this.ImgHeaders[i] = tmp5
	}
	return err
}
func (this *AndroidBootldrQcom) ImgBodies() (v []*AndroidBootldrQcom_ImgBody, err error) {
	if (this._f_imgBodies) {
		return this.imgBodies, nil
	}
	_pos, err := this._io.Pos()
	if err != nil {
		return nil, err
	}
	_, err = this._io.Seek(int64(this.OfsImgBodies), io.SeekStart)
	if err != nil {
		return nil, err
	}
	this.imgBodies = make([]*AndroidBootldrQcom_ImgBody, this.NumImages)
	for i := range this.imgBodies {
		tmp6 := NewAndroidBootldrQcom_ImgBody(i)
		err = tmp6.Read(this._io, this, this._root)
		if err != nil {
			return nil, err
		}
		this.imgBodies[i] = tmp6
	}
	_, err = this._io.Seek(_pos, io.SeekStart)
	if err != nil {
		return nil, err
	}
	this._f_imgBodies = true
	this._f_imgBodies = true
	return this.imgBodies, nil
}

/**
 * According to all available `releasetools.py` versions from AOSP (links are
 * in the top-level `/doc`), this should determine only the size of
 * `img_bodies` - there is [an assertion](
 * https://android.googlesource.com/device/lge/hammerhead/+/7618a7d/releasetools.py#167)
 * for it.
 * 
 * However, files for certain Pixel devices (see `/doc`) apparently declare
 * the entire file size here (i.e. including also fields from `magic` to
 * `img_headers`). So if you interpreted `bootloader_size` as the size of
 * `img_bodies` substream in these files, you would exceed the end of file.
 * Although you could check that it fits in the file before attempting to
 * create a substream of that size, you wouldn't know if it's meant to
 * specify the size of just `img_bodies` or the size of the entire bootloader
 * payload (whereas there may be additional data after the end of payload)
 * until parsing `img_bodies` (or at least summing sizes from `img_headers`,
 * but that's stupid).
 * 
 * So this field isn't reliable enough to be used as the size of any
 * substream. If you want to check if it has a reasonable value, do so in
 * your application code.
 */
type AndroidBootldrQcom_ImgHeader struct {
	Name string
	LenBody uint32
	_io *kaitai.Stream
	_root *AndroidBootldrQcom
	_parent *AndroidBootldrQcom
}
func NewAndroidBootldrQcom_ImgHeader() *AndroidBootldrQcom_ImgHeader {
	return &AndroidBootldrQcom_ImgHeader{
	}
}

func (this *AndroidBootldrQcom_ImgHeader) Read(io *kaitai.Stream, parent *AndroidBootldrQcom, root *AndroidBootldrQcom) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp7, err := this._io.ReadBytes(int(64))
	if err != nil {
		return err
	}
	tmp7 = kaitai.BytesTerminate(tmp7, 0, false)
	this.Name = string(tmp7)
	tmp8, err := this._io.ReadU4le()
	if err != nil {
		return err
	}
	this.LenBody = uint32(tmp8)
	return err
}
type AndroidBootldrQcom_ImgBody struct {
	Body []byte
	Idx int32
	_io *kaitai.Stream
	_root *AndroidBootldrQcom
	_parent *AndroidBootldrQcom
	_f_imgHeader bool
	imgHeader *AndroidBootldrQcom_ImgHeader
}
func NewAndroidBootldrQcom_ImgBody(idx int32) *AndroidBootldrQcom_ImgBody {
	return &AndroidBootldrQcom_ImgBody{
		Idx: idx,
	}
}

func (this *AndroidBootldrQcom_ImgBody) Read(io *kaitai.Stream, parent *AndroidBootldrQcom, root *AndroidBootldrQcom) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp9, err := this.ImgHeader()
	if err != nil {
		return err
	}
	tmp10, err := this._io.ReadBytes(int(tmp9.LenBody))
	if err != nil {
		return err
	}
	tmp10 = tmp10
	this.Body = tmp10
	return err
}
func (this *AndroidBootldrQcom_ImgBody) ImgHeader() (v *AndroidBootldrQcom_ImgHeader, err error) {
	if (this._f_imgHeader) {
		return this.imgHeader, nil
	}
	this.imgHeader = this._root.ImgHeaders[this.Idx]
	this._f_imgHeader = true
	return this.imgHeader, nil
}