Warning: Hindi ako mananagot at responsible sa ano mang mangyari sa unit mo, bago mo pa man i-jailbreak ang device mo dapat alam mo na ang maaring pinsala o kinahihinatnan ng mahal mong gadget.

iPhone 3G users if you rely on ultrasn0w to unlock your device upgrading to 4.2.1 will render your phone locked and you need to upgrade to iPad baseband 6.15 to have your device unlocked again thus rendering your GPS useless and always requires a custom firmware to upgrade and downgrade your device even on an official firmware. However if want to take the risk feel free to use this guide.


Ang guide na ito ay para sa mga iTouch 2G and iPhone 3G users na nais mag-upgrade sa 4.2.1 firmware which is the last firmware for both devices and wants it jailbroken.

Pros

- Great selection of app compatibility, from games, productivity, etc on App Store and Cydia
- Final release supported on second generation devices (iPhone 3G and iPod touch 2G)
- Fixes intermittent Wi-Fi issues
- Find My iPhone location feature is free for this version
- AirPlay (replacement of AirTunes, AirPlay will offer stream video, music, and photos over Wi-Fi)
- Improved Battery Performance
- Security fixes
- Able to create folders to organize apps

Cons

- No multitasking and homescreen wallpaper compared to other iDevices like iTouch 3g/4g and iPhone 3GS/4 (can be enabled through JB)
- Slow and animation lags all the time when Multitasking and homescreen wallpaper is enabled.

Why use 4.2.1?

If you are stuck in your old firmware like 3.1.3, 4.0, 4.1, you are now missing some great apps which requires 4.2.1 at karamihan ng mga cool tweaks sa Cydia requires iOS 4 at least just to use them. Now, if you upgrade to 4.2.1, I strongly suggest not to enable multitasking and the homescreen wallpaper, as well as the unified iPod and battery percentage, because it will really slow your device. The good thing about having 4.2.1 is that you can tweak the firmware to make it fast on your old device, make it responsive, and still enjoy the goodness of the firmware.

Requirements:

- iTouch 2g / iPhone 3G
- 4.2.1 OFW firmware
- redsn0w 0.9.8b4 - iTouch 2G / iphone 3G (iPhone 3G user, factory unlocked can use this version no need for iPad BB 6.15)
- redsn0w 0.9.6rc16 - iPhone 3G
- Windows XP/Vista/7
- Internet Connection

Download Links below:

iTouch 2G 4.2.1
http://appldnld.apple.com/iPhone4/061-9855.20101122.Lrft6/iPod2,1_4.2.1_8C148_Restore.ipsw
iPhone 3G 4.2.1
http://appldnld.apple.com/iPhone4/061-9853.20101122.Vfgt5/iPhone1,2_4.2.1_8C148_Restore.ipsw
redsn0w 0.9.8b4
https://sites.google.com/a/iphone-dev.com/files/home/redsn0w_win_0.9.8b4.zip?attredirects=0
redsn0w 0.9.6rc16
https://sites.google.com/a/iphone-dev.com/files/home/redsn0w_win_0.9.6rc16.zip?attredirects=0&d=1
Instructions

Before restoring or upgrading to 4.2.1 backup your repo packages or sync your device to iTunes.

A. Upgrading / Restoring to 4.2.1

- Download your 4.2.1 firmware on the link provided above
- Open iTunes and make sure you have an internet connection
- Connect your device and wait for iTunes to detect it
- If prompted to upgrade, just cancel it
- Kung 1st time mo mag-upgrade, pindutin mo ang shift key sa keyboard mo tapos click mo upgrade sa iTunes
- Hanapin ang 4.2.1 IPSW tapos click open
- Hintayin si iTunes na mag upgrade ng device mo
- Kung nakagamit ka na ng 4.2.1 before pero nag downgrade, use shift + restore instead na upgrade

B. Jailbreaking

- Download redsn0w and extract all its contents to a folder of your choice.
- Right click on redsn0w at set compatibility to XP SP3 or Vista if you are on windows 7 and run as administrator.





Click "Finish" and wait for the jailbreak process which will take place on your device.

Congratulations! your device is already jailbroken. Run cydia and add your repo sources, install installous and sync your apps to itunes.

For 3G users na gumamit ng iPad BB 6.15 open nyo Cydia and wait for it to finish loading.

- Go to Manage >>> Sources >>> repo666.ultrasn0w.com
- Install ultrasn0w and reboot your device, that should unlock your phone.
- Kung di mo ma activate phone mo re-Jailbreak ka using redsn0w 0.9.8b4 and just check install cydia
- That should activate your phone


I hope that helps ... 

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