Play with the machine and play with the machine---the thinking and analysis process of some Android customized machines to remove the system installation restrictions

 There is not much to explain the meaning of the customized machine, and anyone who understands it can understand it.

In some custom machines, users are restricted from installing apps. When you use a third-party tool or adb command Android app, it will prompt de xxx.apk. autostarter is not auth, install failed! and other similar prompts. In the process of solving similar problems in some customized systems, there are basically the following Several methods.

1-----The first threshold for intercepting app installation is a detection app in the custom system. Used to restrict users from installing apps. The customization system is different. This app is also slightly different. Of course there are some custom systems that don't exist

2----The Services.jar file in the system is decompiled to verify. related code

const-string v3, " is not auth,install failed!"
const-string v7, " is not auth,install failed!"

 In the conversion to java code

if (this . mCert . isCheckAuth( packageName, verifierSig) =true) goto L23;

change into

goto :cond a2; 

The principle is to skip the detection authentication mechanism. Ignore the result

invoke-virtual {v0, v6, v4}， Lcom/vecentek/security2/CertificateManager;->isCheckAuth(l
move-result v0
goto :cond. _f5
.lne 13932
new-instance v0，Ljava/lang/StringBuilder;
invoke -direct {v0}, Ljava/lang/StringBuilder;-> <init>()V
invoke-virtual {vO, v6}, Ljava/lang/StringBuilder:->append(Ljava/lang/String:)Ljava/lang/
const-string v7, ’is not auth,install failed!"

The above is just a brief analysis of the process. However, the version of the customized machine is different, and some need to merge the Services.jar file to perform decompilation. As for how to distinguish whether it needs to be merged, you can check the file size in system----framework----Services.jar. 1K classes are not merged.

Of course, there are other ways to restrict app installation.

There are also some customized machines that do not need the above operations, and only need to flash the official shared general firmware to be a normal machine