add a specification for the bootloader used on several ASUS Android d…

…evices (#472) * add a specification for the bootloader used on several ASUS Android devices. * android_asus_bootldr: add info about test file * android_asus_bootldr: rename `len_image` to `len_body` * android_asus_bootldr: add `valid` checks * android_asus_bootldr: add a value instance `image_name` ... resolving the image file name based on known `magic` strings * android_asus_bootldr: change key order (`size` above `type`) * android_asus_bootldr: rename `magic` to `chunk_id` Co-authored-by: Petr Pucil <[email protected]>
kaitai-io · Jul 5, 2021 · 82d9493 · 82d9493
1 parent 610b7a8
commit 82d9493
Showing 1 changed file with 70 additions and 0 deletions.
diff --git a/archive/android_asus_bootldr.ksy b/archive/android_asus_bootldr.ksy
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+meta:
+  id: android_asus_bootldr
+  title: ASUS Fugu bootloader.img format (version 2 and later)
+  file-extension: img
+  tags:
+    - archive
+    - android
+  license: CC0-1.0
+  ks-version: 0.9
+  encoding: ASCII
+  endian: le
+doc: |
+  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>
+doc-ref: https://android.googlesource.com/device/asus/fugu/+/android-8.1.0_r5/releasetools.py
+seq:
+  - id: magic
+    contents: BOOTLDR!
+  - id: revision
+    type: u2
+    valid:
+      min: 2
+  - id: reserved1
+    type: u2
+  - id: reserved2
+    type: u4
+  - id: images
+    type: image
+    repeat: expr
+    repeat-expr: 3
+    doc: |
+      Only three images are included: `ifwi.bin`, `droidboot.img`
+      and `splashscreen.img`
+types:
+  image:
+    -webide-representation: '{file_name}'
+    seq:
+      - id: chunk_id
+        size: 8
+        type: str
+        valid:
+          any-of:
+            - '"IFWI!!!!"'
+            - '"DROIDBT!"'
+            - '"SPLASHS!"'
+      - id: len_body
+        type: u4
+      - id: flags
+        type: u1
+        valid:
+          expr: _ & 1 != 0
+      - id: reserved1
+        type: u1
+      - id: reserved2
+        type: u1
+      - id: reserved3
+        type: u1
+      - id: body
+        size: len_body
+    instances:
+      file_name:
+        value: |
+          chunk_id == "IFWI!!!!" ? "ifwi.bin" :
+          chunk_id == "DROIDBT!" ? "droidboot.img" :
+          chunk_id == "SPLASHS!" ? "splashscreen.img" :
+          ""