[Galaxy S III Android Development] skyelm:
Works On 32GB I9300 as follows

BACKUP-BACKUP-BACKUP -TO PC OR MicroSD

THIS WILL WIPE YOUR PHONE OF ALL CONTENTS-STUFF-DOCS-PICS-NANDROID EVERYTHING WILL BE GONE

YOU NEED A SD CARD TO REFLASH YOUR PHONE AFTER THIS

ALL CONTENTS-STUFF-DOCS-PICS-NANDROID EVERYTHING WILL BE GONE​

hi guys i did this on my 32GB S3 and it worked flawlessly using [MENTION=4473547]forumber2[/MENTION] zip by editing some values according to my phone storage and requirement.
[MENTION=4473547]forumber2[/MENTION] can add on OP for those that want to do it for whatever partition on your phone

Mandatory Warning - Warning

your phone may die or not work ok forever if you act a fool and set too small partitions

it may just die to spite you or just for fun so be careful if you do this

do a backup because it will delete all your stuff, even cute puppy photos won't be spared

Warning - Warning

text to be typed is in green colour

you'll need these on your PC/Phone

PC

Text editor (Notepad++)

ADB (Android Commangdr or CMD works fine)

Archiver (7Zip)

Phone

insecure adb ( its here on XDA by Chainfire) http://xdaforums.com/showthread.php?t=1687590

Rooted phone (its here on XDA by Chainfire)

parted (i attached it below)

Root Explorer (X-plore,Root Explorer, ES etc etc )

Steps

On Your Phone

1. Parted - using Root Explorer, this file should be put in "system\bin\" then change permission to rwxr-rx-r and REBOOT

2. Insecure adb - install as usual apk file

ON your PC:

3. Connect your phone to PC

4. Open CMD and check your phone is seen/available/online

4.1 type "adb devices" ( you should see a list with a number and device - your good to go else check if debugging is enabled on your phone)

5. Get partition sizes

5.1 type " adb shell "

5.2 type " parted /dev/block/mmcblk0 print "

this will give you a printout of your device partitions with names

Save this screenshot if you want to rollback to default values later on

a PIT file will also do the same thing via ODIN

6. extract the repart_16GB_GT-I9300_CWM.zip

7. open the extracted folder \META-INF\com\google\android\

8. open "update-binary" with Notepad++

9. change the following 5 lines to sizes you want

Very important

the last line(31.3GB) is from your print above on point 5.2

don't put numbers you from thin air - think about it

ui_print "Creating new partitions..."

parted /dev/block/mmcblk0 mkpart primary 92.3MB 193MB

parted /dev/block/mmcblk0 mkpart primary 193MB 1805MB

parted /dev/block/mmcblk0 mkpart primary 1805MB 1820MB

parted /dev/block/mmcblk0 mkpart primary 1820MB 1828MB

parted /dev/block/mmcblk0 mkpart primary 1828MB 31.3GB

10. after editing then save the file

drag it into the zip

then copy the zip to your phone and flash via CWM...done

now the pain starts of putting everything you've backed up back to your phone and install your apps for a small gain of 1.5GB... EISH NEH

First one is Cache =100MB

Second is System =1612MB

Third is Hidden/preload =

Fourth is OTA = 8MB

Fifth is UserData = 29.4GB

simple maths 193-92.3 = 100MB is patition size

the other way is to ask yourself how much space you want and add together with the last number with the size you want

"i want System to be 2GB=2000MB then 193+2000=2193MB"

don't be greedy and unreasonable and want space you don't have like 64GB on a 32GB S3... not going to happen, you'll kill your phone

rolling back is also the same way - remember the screenshot on point 5.2 YEAH that one you were suppose to save is needed here

---------- Post added at 04:48 PM ---------- Previous post was at 04:19 PM ----------

I'm going to shrink my system to 512MB and install CM or SlimKat , currently with preload and cache shrunk