[General Questions and Answers] Descent2:
Hey midnite_,

I am a newbie too and have a lot of blank spots in my understanding of what we can do with android. I also came here with same question. I found how to root, this isn't a secret. Like you, I want to know how do I fix it if I break it.

So, with regards to your questions.

1. Unlock the bootloader

Not clear on this one, as not every tutorial even mentions this part. My feeling is that this might be specific to some phones, like HTC.

2. Flash Custom Recovery (such as AmonRa, CWR, TWRP...)

Recovery is an intermediate stage of phone booting process after bootloader but before OS.

It is there to allow OTA (Over the air) updates. During those, the OS is halted and replaced with a newer one.

What this means for us is that the recovery is capable of replacing OS (ROM - are these terms interchangeable?).

Recovery is the same as hidden partition on windows, that is sometimes present on a PC. It has a limited interface.

It can replace one OS image with another. It probably checks the checksum and creates the new one after the update. It is probably the gatekeeper.

Stock recovery will not replace OS with an image from SD card or from PC through USB. Only OTA.

This is the reason for flashing the custom (hacked) recovery on.

Custom recovery is made to allow additional options, such as allowing image sources such as PC or SD card, and also a ROM backup (write OS image to PC).

3. Flash update file using "upgrade from SD card" function of custom recovery now in place.

In this step, the Superuser.apk and bin files are placed. Stock recovery will not let us do that.

Also, I think the reason we can't just use ADB to "copy" superuser package to phone is because the system is either running or exists as an image (compressed?), and is probably protective of its modification. (So, likely the superuser package also replaces the checksum that the OS uses to check if it has been compromised?) Yes, this modifies your rom.

I assume that unrooting could be done after this by updating again with a file that removes superuser package and that would make your rom stock again.

4 OR flash custom ROM, which usually includes superuser package. Of course using custom rom means you no longer have stock rom.

To have a backup of original ROM, you would :

1 Unlock bootloader,

2 Flash (install) custom recovery

3 superuser doesn't matter here

4 Use custom recovery function to back up your stock ROM.

I want to know the answers to the rest of your questions as well as some clarifications to mine.

Personally, I am looking for a way to backup the stock recovery as well.

I know there are some people asking about this. The procedure appears to be as follows:

(pieced together so don't take it as a tutorial)

1 Unlock bootloader (again, unclear on this. Also some mention S-OFF and others don't)

2 With USB debugging allowed (meaning connect as device requiring a driver), Connect to a PC with ABD, and a driver installed.

3 From ADB, issue a command "adb boot recoveryimage.name" instead of the usual "adb flash recoveryimage.name".

This will make the phone boot into a custom recovery image that is residing on PC, without first writing it to the phone.

4 Unclear how, but make that custom recovery now being live to back up stock rom to pc.

5 Unclear how, but make that custom recovery now being live to flash either root or custom rom to the phone.

6 Disconnect, reboot the phone. Once in OS, use root privileges to mount recovery partition ? (this makes it visible as drive)

7 Don't know how, but use root privileges to back up now visible stock recovery partition to PC as image.

( This should give you two out of three original parts.)

Keep in mind that even if my peace-by-peace "know-how" ever works, there is at least one clearly faulty step:

The back up of the original state of the boot loader has been never made. I do not know if it is easily can be toggled back and forth from lock to unlock and back without leaving any trace. Also, like yourself, I probably don't quite understand what am I talking about, but I have tried to make as much sense of what I have read here and there.

This is my first smart phone, and my experience with linux is limited to building a minecraft server on MineOS, which was pre-made so that not much was required to make it run. I have "mounted" a partition for the first time last week, trying to break Win7recovery, booting it with Knoppix. This is why I think this is probably will come in play here too, as the recovery partition on W7 was hidden. Until then I didn't understand what mounting means, as windows always does it for you. So, take everything I say with a bunch of salt.

Please, let me know too, if you find out more. I want to flash the hell out of my Prism, but I want to be smart about it.