[Galaxy Y GT-S5360 General] kurotsugi:
WARNING: THIS MOD IS INTENDED FOR ADVANCED USER

this mod is difficult to applied. for an easier method, you can use my guide here about increasing internal memory without dualboot kernel. if you want a NEW-BETTER-FASTER-BUGLESS method to save your internal memory, you can use my akuro mod in this thread

anyway, this is only one of dualboot implementation based on irfanbagus's work. I actually doing this for fun. this mod is actually intended for rom development for any rom dev who want to develop a custom rom without a risk got a bootloop in his device. please feel free to discuss all stuff about dualboot mod or how to enhance it but don't ask about how to install it on your device. if you don't know how to install it, it means this mod doesn't suitable for you. don't worry. there's a lot of alternative method to save your internal memory space as I've stated above.

let's get straight on how we do this. first of all, in this mod the second ROM will installed on sdcard with modified partition size. we'll make bigger partition on data and system partition. please look into the picture below.

requirement:

1. know how to customize a rom.

2. know how to install a custom kernel

3. know how to partition sdcard, and of course

3. a sdcard minimal 8gb class 6.

what you'll nedd:

1. a custom rom to be modified.

2. a dualboot custom kernel. you can get it here. http://www.mediafire.com/?6zrkh6a872036x7

3. a modified rom installer script. http://www.mediafire.com/download.php?nxgiz0993brp9re

4. a partition tools.

5. all things needed to modify a rom.

the steps:

1. >>>SDCARD PARTITION<<<

make 4 partition on your sdcard. all partition is primary. my recommended setting for all partition is. 6gb fat32 on first partition, 300mb ext3 on 2nd partition, 300mb ext3 for 3rd partition, and the rest ext3 for 4th partition. you can modify the the 1st and 4th size but don't change the 2nd and 3rd partition size.

2. >>>install irfan's dualboot kernel<<<

feel free to use any method to install the kernel. you can use mai77's, faqbly's method or odin to install the kernel.

3. >>>ROM preparation<<<

extract your custom rom. replace meta-inf folder with the one I've give to you. this script will install your rom to your sdcard partition. re-zip the rom, then copy it to your formatted sdcard (in the 1st partition of course). if these script didn't work check irfan's original post for detailed guide on modifying installer script here http://xdaforums.com/showthread.php?t=1598803

4. >>>dual boot setting and ROM installation<<<

create a blank file in sdcard named 'bootsdcard' then go to recovery mode. install your custom rom. wait till it finished then reboot. the first installation will take a longer than the usual. be patient.

finish. enjoy your 2nd rom with larger /data and /system partition

========

there are several possibilities on installing the new rom. in most cases, it have succesfully installed the rom (I've got no report on installation failure till this moment). but if the rom doesn't work, you'll need to modify the rom and the installer script.

DISCLAIMER:

1. DO IT WITH YOUR OWN RISK.

2. the succession rate is depend on your custom rom and your sdcard quality. do your best to modify it.

3. don't use a2sd or link2sd

4. don't install the app on sdcard when you use the 2nd rom.

5. it will get laggy if your sdcard is not fast enough. you'll need a faster one.

6. this mood will make your battery drains faster. please be cautious.

credits:

1. myss ROM developer. my installation script is based on it.

2. irfanbagus, for the dualboot kernel and his helpfull guide.

3. all XDA member who have share their knowledge for us.

I'm a chemist student. another mid-user here. no need to give thanks. give them to the dev instead.

UPDATE:

http://www.mediafire.com/download.php?hw9jgrui1ga4akg

this is another updater script which automatically delete your sdcard's /data partition.

savie have made another kernel with dualboot support. if you feel this kernel doesn't fit with your necessity, you can use savie's one you can get his kernel in dev section [url="http://xdaforums.com/showthread.php?t=1761166]here[/url]