recently I found that, I can use cmd "adb install -r" to replace a build-in system package. of course, the two package use the same certificate.
but android 1.1 / 1.0 we cant not re-install a system package. I look over the code PackageManagerService.java, android 1.0 if find the package is a system package, the deletePackageLI() function will return false, and then the installPackageLI() will return PackageManager.INSTALL_FAILED_REPLACE_COULDNT_DELETE. but android 1.5 changed this. it is allowed to replace a system package. but use the signature mechanism to protect it. I do not know whether my understand is correct. and it is not safe is the user can replace a system package i think. except the OEM use their own signature, others can not get this certificate. pls give me some help whether my understand is correct. thanks. cht
