Android POTA升级包定制，移除不需要更新的分区，重新打包签名

Posted 2022-06-25 阿迷创客

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文章目录

1.前言

最近在做MTK android 9.0 的投影项目，使用的是9269芯片，其中有一个功能是投影方位的设定，如正装正投、正装背投。但MTK目前软件架构上，数据耦合度还是很高，没有分离到数据分区，投影方位的设定耦合在/vendor/tvconfig/config/model/customer_1.ini文件中。而公版OTA又不支持差分升级，所以就想到了定制OTA包的方法，大致思路就是解压当前ZIP包，编辑，重新打包，签名。

2.基本步骤

1.AOSP编译生成OTA包:mt5862_bga_1g-ota_update.zip
2.unzip 解压 mt5862_bga_1g-ota_update.zip
3.编辑解压后的文件，例如本文移除了tvconfig.img
4.重新压缩打包update.zip
5.签名
6.验证修改后的ota包

3.详细过程

3.1 解压update.zip到指定目录

将编译生成的ota包mt5862_bga_1g-ota_update.zip放置到如下目录，方便操作
- PATH:vendor/mediatek/proprietary_tv/open/common/security
- 选择这个目录，主要是因为所使用的签名文件都在这个路径下，输入命令时候可以少打几个路径
创建临时目录: $mkdir ota_dir
$mv mt5862_bga_1g-ota_update.zip ota_dir/
$cd ota_dir
$unzip mt5862_bga_1g-ota_update.zip

builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security$ls
adb       media.pk8       mt5862_bga_1g-ota_update.zip  platform.pk8       releasekey.pk8       shared.pk8       testkey.pk8  avb_keys  media.x509.pem  platform.x509.pem  releasekey.x509.pem  shared.x509.pem  testkey.x509.pem
builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security$
builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security$mkdir ota_dir
builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security$mv mt5862_bga_1g-ota_update.zip  ota_dir/
builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security/ota_dir$unzip mt5862_bga_1g-ota_update.zip 
Archive:  mt5862_bga_1g-ota_update.zip
signed by SignApk
 extracting: META-INF/com/android/metadata  
 extracting: compatibility.zip       
 extracting: system.new.dat.br       
 extracting: system.patch.dat        
 extracting: vendor.new.dat.br       
 extracting: vendor.patch.dat        
  inflating: 3rd_a.img               
  inflating: 3rd_rw.img              
  inflating: FRC-R2.bin              
  inflating: META-INF/com/google/android/update-binary  
  inflating: META-INF/com/google/android/updater-script  
  inflating: RT_PM.bin               
  inflating: bl31.aes                
  inflating: boot.img                
  inflating: dtb.bin                 
  inflating: factory_a.img           
  inflating: linux_rootfs_a.img      
  inflating: mboot.bin               
  inflating: rom_emmc_boot.bin       
  inflating: system.transfer.list    
  inflating: tee.aes                 
  inflating: tvcertificate.img       
  inflating: tvconfig.img            
  inflating: tvservice.img           
  inflating: vendor.transfer.list    
  inflating: META-INF/com/android/otacert  
builder@mm-android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security/ota_dir$
mv mt5862_bga_1g-ota_update.zip  ../

3.2 编辑OTA文件

目标：移除tvconfig文件，即OTA不升级此分区

3.2.1 编辑 updater-script

路径：ota_dir\\META-INF\\com\\google\\android\\updater-script
移除升级脚本中关于tvconfig的部分

package_extract_file("tvconfig.img", "/dev/block/platform/mstar_mci.0/by-name/tvconfig");

3.2.2 删除tvconfig.img文件

删除 ota_dir\\tvconfig.img 文件

3.2.3 确认OTA签名文件

打开如下文件，后续重新签名后，签名文件要和此文件一致，否则OTA升级时候验证会失败

ota_dir\\META-INF\\com\\android\\otacert

-----BEGIN CERTIFICATE-----
……省略……
XXXXXXXXXXXXXXXXXXXXXX/LfA==
-----END CERTIFICATE-----

3.3 重新打包OTA ZIP包

压缩：$zip -qry update.unsigned.zip ota_dir/

builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security$zip -qry update.unsigned.zip ota_dir/
builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security$ls
adb        media.x509.pem                platform.pk8       releasekey.x509.pem  testkey.pk8
avb_keys   mt5862_bga_1g-ota_update.zip  platform.x509.pem  shared.pk8           testkey.x509.pem
media.pk8  ota_dir                       releasekey.pk8     shared.x509.pem      update.unsigned.zip
builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security$

3.4 重新签名

3.4.1 签名

命令：$java -Xmx512m -jar -Djava.library.path=“/home/code/out/host/linux-x86/lib64/” /home/code/out/host/linux-x86/framework/signapk.jar -w releasekey.x509.pem releasekey.pk8 update.unsigned.zip update.signed.zip

builder@android(master):~/code/vendor/mediatek/proprietary_tv/open/common/security$java  -Xmx512m -jar  -Djava.library.path="/home/code/out/host/linux-x86/lib64/"  /home/code/out/host/linux-x86/framework/signapk.jar -w releasekey.x509.pem releasekey.pk8    update.unsigned.zip update.signed.zip