Note: If you need to fix the fastboot/droidboot/bootloader only, then proceed upto step 15 but you need to get the right fastboot.img file from the firmware.
1. Before you begin, u should prepare your pc with the required drivers.
2. Dowload USB driver and install: https://software.intel.com/en-us/and...ndroid-devices
3. Dowload and install iSocUSB driver: http://www.mediafire.com/download/7u...etup-1.0.4.exe
4. Download this fastboot-2.19.img.pos.bin file: http://www.mediafire.com/download/6i...19.img.pos.bin
5. Download this and unzip: https://drive.google.com/file/d/0B3v...VTYmFVcXc/view
6. Copy fastboot-2.19.img.pos.bin file to Asus Zenfone 5 A500CG Debrick folder. Search droidboot.img.POS_sign.bin file in the folder and delete it. Rename fastboot-2.19.img.pos.bin to droidboot.img.POS_sign.bin.
7. Copy fastboot-2.19.img.pos.bin file to Asus Zenfone 5 A500CG Debrick folder again. Search droidboot_sign.bin file in the folder and delete it. And again rename fastboot-2.19.img.pos - Copy.bin to droidboot_sign.bin. The existing droidboot.img.POS_sign.bin and droidboot_sign.bin files didn't work for me so I had to replace it with proper file.
8. Download UL-ASUS_T00F-WW-2.21.40.30-user.zip firmware for your specific SKU(WW/TW/CN/CHT) and copy to Asus Zenfone 5 A500CG Debrick folder: https://www.asus.com/id/support/Down...Hp1VKV4Rdz/32/
9. Copy and paste the fastboot.img, boot.img, recovery.img files from the firmware to Asus Zenfone 5 A500CG Debrick folder.
10. Now the process begins. Turn off your device. Lolz, make sure you turn it off. Sometimes it's very confusing to identify whether it's on or off.11. Keep on pressed the volume down key and connect USB cable. Your PC should get the device in Cloverview mode. If not, install the above drivers again.
12. When the device is connected as Cloverview, release volume down key and run Debrick.bat in Asus Zenfone 5 A500CG Debrick folder. You should see some dots, then a big number, then again dots, and then some commands with xfstk........
13. Force turn off the device. Reboot to bootloader(Vol up+Power) and run sec_offline_update_image.cmd in Asus Zenfone 5 A500CG Debrick folder. It will fix your partition table. Let it reboot, if not, force a reboot. For me, it booted properly but my touch screen was not working. If you face the same, don't worry.
14. Reboot to bootloader again and open CMD in Asus Zenfone 5 A500CG Debrick folder and run
fastboot flash fastboot fastboot.img fastboot reboot-bootloader
16. Run
fastboot flash boot boot.img fastboot flash recovery recovery.img
17. We have flashed fastboot, boot, and recovery for 2.21.40.30 but the system is not flashed yet.
18. You have everything fixed so start with the process to re-flash UL-ASUS_T00F-WW-2.21.40.30-user.zip firmware.
19. Reboot to bootloader by Vol up + Power button pressed.
20. Select recovery to reboot to recovery.
21. Select wipe user data and wipe cache.
22. Select apply update with adb and run
adb sideload UL-ASUS_T00F-WW-2.21.40.30-user.zip
24. Hit Thanks! Lolz
25. You just debricked.
Credit goes to: @dgadelha, @shakalaca, @quanganh2627, @swiczak
Let me know if you face any problem. Good luck.
Kunjungi : http://forum.xda-developers.com/zenfone-5/help/debrick-asus-zenfoen-5-fastboot-t3377455