In the last chapter, we learnt to enable Houdini in the Android emulator using our own x86emu device. With that, we can move on to more challenging tasks in the next few chapters. Most device- or system-level customization will involve changes to the Android system start up sequence. In this chapter, we will analyze the Android system start up sequence and learn the knowledge related to the customization and debugging of the start up sequence. In this chapter, we will cover the following topics:

• Android start up process analysis
• Starting up process for the Android-x86
• Creating a filesystem for the Android-x86 initrd.img

We will start with the analysis of a normal Android boot up process. After that, we will introduce the Android-x86 two-stage boot up. We will build a filesystem for the Android emulator that can work with Android-x86 initrd.img. This method provides a flexible way to help the debugging of start up process.