How to Downgrade ASUS Zenfone 4 A400CG from Lollipop 5.0 to Kitkat 4.4

Today ASUS Zenfone Blog will show you How to Downgrade ASUS Zenfone 4 A400CG From Lollipop to KitKat.

Downgrade Step (From L to KK)

1. Download the downgrade tool: UL-ASUS_T00I-WW-9.9.9.0-user.zip
2. Using MTP connecting A400L with PC. (Enable MTP: Setting-->Storage-->press the USB icon on right corner--> Enable MTP)
3. Copy the tool (V9.9.9.0) to the A400CG internal storage.
4. Remove the USB cable, the device will pops up the system upgrade information.
5. After downgraded, device will auto reboot and perform factory reset.
6. After finished, please go to Settings->About-> software information->Build number. The version should be V6.6.3

ZENFONE 4 Downgrade Version
WW VERSION

Description

ASUS ZenFone 4(A400CG) downgrade SOP (Downgrade from L to KK), V9.9.9.0 Only for WW SKU* Notice: 1. Only apply to same SKU update, Example: WW->WW, CN->CN, TW->TW. 2. Software update cannot transfer the software SKU and downgrade the software version. 3. Downgrade image will only revert back to latest KK version 4. After OTA downgrade, device will perform factory reset automatically.then reboot automatically to complete upgrade process 5. System upgrade may cause part of data missing, please buckup your important data before system upgrade

File Size	825 MBytes                                                                              2015/05/29
Download from	Global

ZENFONE 4 Downgrade Version
CHT VERSION

Description

ASUS ZenFone 4(A400CG) downgrade SOP (Downgrade from L to KK), V9.9.9.0 Only for CHT SKU* Notice: 1. Only apply to same SKU update, Example: WW->WW, CN->CN, TW->TW. 2. Software update cannot transfer the software SKU and downgrade the software version. 3. Downgrade image will only revert back to latest KK version 4. After OTA downgrade, device will perform factory reset automatically.then reboot automatically to complete upgrade process 5. System upgrade may cause part of data missing, please buckup your important data before system upgrade

File Size	866 MBytes                                                                              2015/05/26
Download from	Global

TW available Soon