How to add assets to android apk file
I need to update a firmware binary which was packaged into apk file, unfortunately
I do not have the source code of this apk, so I cannot just do mm to regenerate
a new one, I can file a request to ask whom have the source code to do so for me,
but it takes time, and what if I need to do this kind of job frequently.
Here is how to do this, in simple two steps:
Add assets to apk with aapt
aapt was shipped with android sdk, you can find it in build-tools/28.0.2,
for this step only two subcommands are used:
$ aapt r[emove] [-v] file.{zip,jar,apk} file1 [file2 ...]
Delete specified files from Zip-compatible archive.
$ aapt a[dd] [-v] file.{zip,jar,apk} file1 [file2 ...]
Add specified files to Zip-compatible archive.
I need to remove the previous one, or aapt will report file alrady exists issue, do this with:
$ aapt remove -v test.apk assets/fw/bootcode.bin
Now, I can add asset with below command:
$ aapt add -v test.apk assets/fw/bootcode.bin
'assets/fw/bootcode.bin'...
Check with aapt list to see the asset file that has been added:
$ aapt list -v test-signed.apk
Archive: test-signed.apk
Length Method Size Ratio Offset Date Time CRC-32 Name
-------- ------ ------- ----- ------- ---- ---- ------ ----
9193 Stored 9193 0% 0 01-01-09 00:00 5f8a1eb4 res/mipmap-hdpi-v4/ic_launcher.png
5057 Stored 5057 0% 9269 01-01-09 00:00 ffffffffa5bfa0ca res/mipmap-mdpi-v4/ic_launcher.png
14068 Stored 14068 0% 14397 01-01-09 00:00 ffffffffc9c090e8 res/mipmap-xhdpi-v4/ic_launcher.png
23292 Stored 23292 0% 28536 01-01-09 00:00 668d571e res/mipmap-xxhdpi-v4/ic_launcher.png
2348 Stored 2348 0% 51900 01-01-09 00:00 47e2fab3 resources.arsc
2316 Deflate 848 63% 54300 01-01-09 00:00 1be07718 AndroidManifest.xml
52116 Deflate 28943 44% 55213 01-01-09 00:00 ffffffff8e8f907e assets/fw/bootcode.bin
25944 Deflate 12881 50% 84224 01-01-09 00:00 ffffffffe12c80d9 classes.dex
2636 Deflate 851 68% 97162 01-01-09 00:00 ffffffffe66386d2 res/layout/activity_main.xml
848 Deflate 462 46% 98087 01-01-09 00:00 3b233fe5 META-INF/CERT.SF
1714 Deflate 1154 33% 98611 01-01-09 00:00 1977455b META-INF/CERT.RSA
786 Deflate 416 47% 99828 01-01-09 00:00 fffffffff05ab7c6 META-INF/MANIFEST.MF
-------- ------- --- -------
140318 99513 29% 12 files
Re-sign apk with platform key/certificate pair
The apk file was signed with platform signature, as apk signing was file based,
so I need to sign it, as we’ve added asset, or it will report below message when
doing pm -r install:
Failure [INSTALL_PARSE_FAILED_CERTIFICATE_ENCODING: Failed to collect certificates from /data/app/vmdl1616860685.tmp/base.apk: android.content.pm.PackageParser$PackageParserException: Package /data/app/vmdl1616860685.tmp/base.apk has no certificates at entry assets/fw/bootcode.bin: Package /data/app/vmdl1616860685.tmp/base.apk has no certificates at entry assets/fw/bootcode.bin]
To do apk signing, you need to get these files from android source tree:
| files | directory |
|---|---|
| libconscrypt_openjdk_jni.so | prebuilts/sdk/tools/linux/lib64 |
| signapk.jar | prebuilts/sdk/tools/lib/signapk.jar |
| platform.x509.pem | build/target/product/security |
| platform.pk8 | build/target/product/security |
Copy these files to your workspace and sign with:
java -Djava.library.path=. -jar signapk.jar \
platform.x509.pem platform.pk8 \
test.apk test-signed.apk
Before install to the system, verify with jarsigner:
$ jarsigner -verify -verbose -certs test-signed.apk
The signed files will be tagged with sm:
sm 52116 Thu Jan 01 00:00:00 CST 2009 assets/fw/bootcode.bin
Check out the meanings of sm at the end of jarsigner output:
s = signature was verified
m = entry is listed in manifest
Now you can install this signed apk.