[HTC Sensation] Firefall!:
Last updated 7th August 2011

@ mods: Feel free to make this a sticky if you think it's useful.

I am still quite new to Android, and I have come across very many technical terms that I didn't or sitll don't understand, mostly related to rooting your phone. I am not aware if some of these terms are specific to the Sensation, or to HTC devices in general. I create this thread to provide a kind of dictionary explaining this stuff for people who have not heard of it before. As I mentioned, I am not exactly an expert, so I need your contribution. Please correct me if I am wrong and supply the terms that I forgot.

S-OFF / S-ON

A device can be either S-OFF or S-ON. When it's S-ON, your system files/directories are protected against changes. You can't modify them, or at least not permantenly. WHen it's S-OFF, these things become writable: The protection is removed. Additionally, S-ON devices will check signatures of any ROMs you are trying to install, making it impossible to install custom ROMs, whereas S-OFF allows you to install whatever ROM you want. In order to root your device, you will need S-OFF because rooting changes the system. In order to get S-OFF for HTC Sensation, visit http://revolutionary.io/ and check out the guide here: http://xdaforums.com/showthread.php?t=1192300

HTC will soon release its own method to get S-OFF, but their process will possibly void your warranty, whatever.

Another explanation: S-ON/S-OFF is security on/off. If it is ON then a unique signing key from HTC is looked for by HBOOT before allowing something to be flashed. We don't have the key so no ROMs or anything fun until we can get S-OFF. S-OFF doesn't look for that key so we can do whatever we want.

Another Explanation: S-off means that the phone doesn't overwrite /system changes on boot. Eg when devs are testing software, it doesn't get overwritten when rebooting. At the same time it enables permanent root on reboots. S-on will overwrite changes in /system and reset /system to stock ROM on every boot.

Root / su

On a new device, you perform your actions as a kind of inferior user. The system does not allow you to perform critical operations such as changing the CPU clock. When you root your device, you will be an administrator (i.e. root user) and able to do anything you want. S-OFF is required for root. su is the name of the executable that grants you root access. (su stands for super user).

Hboot

Hboot is the boot sector of your device. When you turn on your phone, it's the first thing that comes to live and it then loads the rest of your system. "to boot into hboot" actually means to interrupt this process and stay in Hboot, allowing you to reset your device and perform firmware upgrades etc. In order to do that, press and hold the Volume Down key while turning on the phone.

CID

It's your carrier's unique identifier. It has information like the country and a carrier code assigned by ITU (UN's telecom regulation department I believe).

11111111 is SuperCID, this allows you to install any signed RUU without regional restrictions.

fastboot

Essentially the equivalent of hibernate windows. It writes the RAM and such to memory so when your turn your phone on it loads the previous state into RAM instead of actually loading the whole system again.

USB debugging

Allows you to use adb commands on your phone. Carriers usually leave it off for security I guess. Not so sure...

Partitions

If somebody knows more about the individual partition layout (recovery, system, and so on) please post your knowledge!

Android SDK

The Android SDK (Software Development Kit) is a suite of tools used by Android developers.

adb

adb is part of the Android SDK and allows you to interact with your phone when connected to your computer. It allows you to send commands to your device, it can provide you with a remote shell.

fre3vo / temproot / permroot

fre3vo is a tool originally developed for the HTC Evo 3D that provides temporary root access for the Sensation as well. It is now kind of obsolete as permanent root has become available.

ClockworkMod (CWM)

Clockworkmod is a 3rd party tool that you can install to the recovery partition on your phone to replace the stock recovery application. It comes with many useful features such as a backup manager and allows you to install ROMs, etc. easily.

Also, someone please explain how "unlocking the bootloader" is related to S-OFF/S-ON and/or hboot