Monday, May 25, 2009

Android G1 Cupcake hacking links/summary

I have the G1 dev phone, but with the recent cupcake update, it got reverted to T-Mobile's stock OS. In particular I lost root on the phone. I ended up installing the JesusFreke OS on the phone, which is working well. Here's what I figured out along the way.

There are a few important concepts in G1 modding (please correct me where I'm wrong):
  • SPL: The Secondary-Program-Loader is a piece of firmware that is basically the bootloader - it loads the OS. You want to replace this with a more fully functional version. I use the HardSPL loader. This loader, as well as some of the other ones out there, gives you the option to use fastboot (here or here), which lets you install on partitions on the phone and boot.
  • Recovery partition: There is a partition on the phone that has a kernel that is used only when the phone is booted into recovery mode (turn on holding power and home at the same time, then press alt+l to get to the menu). Installing a custom image here, like from android-roms, gives you an extra option in the recovery menu to use nandroid to backup your entire system (not sure if it includes the sdcard). Usefull if you want to fiddle with your firmware or wiping your phone and want to be able to restore.
  • System ROM: This is the system that runs during normal booting and operation. I replaced this with JesusFreke using instructions here. It gives you a kernel set up for wifi-tether, and also includes a couple of extra neat things like the ability to multi-touch pinch zoom in and out on the browser. If you're just interested in wifi-teher, you probably don't need JesusFreke's ROM. The wifi-tether link has an alternate kernel that is a smaller mod. Note that installing the JesusFreke ROM recommends wiping the data on the phone.

Android-roms at is a useful site that pulls together most of this info. JesusFreke's blog has details on each ROM release and what was changed from the stock ROM.

Finally, if you have an android dev phone and lost root with the cupcake update. The directions at worked for me to regain it. I think these directions require the custom SPL, such as HardSPL.

1 comment:

  1. Hi Josh,

    Could you help me out tehthering my G1 (which I have since beginning of this year) to my pc. It's rather unclear to me how to go about, with versions, licences and all that. Why so complicated?


    Maastricht, Netherlands