[HTC Desire S] enigmaamit:
Converting partitions and backups from ext3 to ext4

@ Harsh, regarding my earlier commitment on helping you with the partition conversion and advanced restore:

Before you do any of this,

1. Take a nandroid backup. The whole procedure below is utterly harmless but you should develop a habit of doing this whenever you play around with anything.

2. Make sure you have at least 50% charge, and preferably have it plugged into your laptop. The reasons are pretty obvious.. first, you dont want to run out of charge while doing something as grass-root level as this, and secondly, having hooked it up to a laptop, adb access is available to start with. (i'm assuming you have adb set up on your pc)

3. Make sure you have adequate free space on your sd card. I would recommend around 1.5 to 2 GB. This is because when changing a file system the recovery first backs up your data from the partition onto the sd card, formats the partition into the new file system and then moves the data back into the partition after that into the new file system (ext4, in our case). So you need to give enough room for the recovery to be able to temporarily cache the contents of the partitions on the sd card. Hope this is clear to you.

EDIT: Don't worry about insufficient space on your sd card screwing up this process. Because since the 2.2.7 version, 4ext calculates the actual required free space needed for a conversion of a selected partition before it even starts doing that. If space needed is too low it won't do the conversion.

Let us begin:

1.) To convert existing file system:

To convert your existing file system, go into recovery and see what the partitions are right now. You'll see four partitions: 1. system, 2. data, 3. cache, 4. sd card

Next to these you'll see the file system they're on. I'm guessing it will look something like ext4, ext3, ext3, fat32 respectively, if you're coming from ClockWorkMod recovery. What you need to do to convert the ext3 partitions to ext4 is go to the EXT3 - 4EXT - EXT4 option in the menu and once inside, choose the first option (convert l change a backup -> ext4).

In that sub-menu, choose the partition you want to convert. (2nd, 3rd and 4th options SYSTEM, DATA & CACHE respectively). The execute menu will prompt you regarding going ahead. Select Yes - do it!

Now the process that i had described earlier will begin and at the end you'll have all your original data on the ext4 file system on whichever partition you selected.

Do the same for each partition that is in ext3 format.

2.) To change file system for old backups:

Again, if you want to change one of your old backups that you took while on CWM Recovery (which were most probably taken in ext3 default format), you need to convert them to ext4, otherwise 4EXT Recovery will restore them to their default file system (another neat feature of this recovery) as a safeguard against restore onto contrasting file systems.

To do this, go to EXT3 - 4EXT - EXT4 menu > then convert l change a backup -> EXT4 > THEN change one of your backups > now select the backup you want to change to ext4 > at the prompt menu, select Yes, do it!

Once you've done this, you'll get a hang of what all the other sub menus are for... You'll figure them out on your own in no time.

Whew! That was long and tedious... But i've tried to be as elaborate as i can for all those users new to 4EXT and apprehensive about migrating. I've also posted this in the General section in the relevant thread.

I remember how i was before i converted for the first time and there was no detailed guide available.

Hope this has helped!!

P.S. Thanks to Madmaxx for the tips and inputs that helped me write this mini tutorial.