INTRODUCTION
Some updates won't install no matter what. You did everything, automatic or manual flash, all you get is assert errors or the update simply won't appear. Or you modified your system (even just build.prop) and now you have to reflash to get rid of the update errors. That's where ADB sideloading comes in handy. This will allow you to flash a full firmware zip file so you can finally install that latest update. This also works for update firmware zips.
NOTICE
This may require advanced knowledge of how Device Manager and drivers installation work in Windows. This document will be edited to reflect any changes to the procedure, as well as provide links to the latest full/update firmware zips. The instructions assume you're using Windows 7/8/8.1 so it might be a bit different for previous or future Windows versions.
WARNING
Make sure you have the correct firmware for your device, especially for update firmware zips. You can't update TW with WW firmware.
Flashing instructions are not confirmed for Zenfone 5 LTE.
REQUIREMENTS
ASUS Zenfone 5/5 Lite/5 LTE
Windows-based PC (Windows XP, Vista, 7, 8, 8.1, 10)
ADB, fastboot and drivers installer 1.0.32 for Lollipop firmware
Full/update firmware zip (see links below)
USB debugging enabled
DOWNLOAD LINKS
Full firmware zip for ASUS Zenfone 5 A501CG/ASUS_T00J
3.23.40.78 WW [Lollipop 5.0] - Release notes
2.22.40.54 WW MR11.2 [KitKat to Lollipop bridge manual OTA, required for Lollipop update] - Release notes
Full firmware zip for Zenfone 5 Lite A502CG/ASUS_T00K
2.21.40.61 MR2.0 WW [KitKat 4.4.2] - Release notes
Full firmware zip for Zenfone 5 LTE A500KL/ASUS_T00P
12.4.5.50 WW [Lollipop 5.0] - Release notes
INSTRUCTIONS
Install ADB, fastboot and drivers using instructions in the link above.
Connect your Zenfone 5 to your PC and turn on USB debugging. The drivers should install automatically, if they don't, you have to manually update driver software in Device Manager.
Browse to the folder where you saved your full/update firmware zip, Shift+right-click, then click "Open command window here".
On the command prompt that opens, enter without quotes: "adb reboot bootloader".
The device should reboot to Droidboot mode, and drivers should install automatically, if they don't, manually update driver software.
Scroll to the "Recovery" entry on Droidboot using the volume buttons, then select using the power button. The device should reboot to recovery mode.
On the "No command" screen, follow the steps here if you're on KitKat, or here if you're on Lollipop. Select "Apply update from adb".
On the command prompt, enter without quotes: "adb sideload filename.zip" (example: adb sideload UL-ASUS_T00F-WW-3.23.40.60-user.zip). Wait for the transfer to finish.
After the transfer, your device should detect a firmware update and start to flash. Watch out for any errors.
If the flashing is successful, do a factory reset (for stability purposes).
If you get stuck in the USB logo (flash mode) screen, proceed to the fix instructions below.
You can now try an automatic or manual flash of the latest firmware, either using this method or via the device.
INSTRUCTIONS FOR FIXING BOOTLOOP
Download full/update firmware zip, and extract a copy of the recovery.img from the zip file. Keep both files in one folder.
Install ADB, fastboot and drivers using instructions in the link above.
Hold power button for 10 seconds to make sure the device is completely turned off.
Hold volume up+power to boot to Droidboot mode, and drivers should install automatically, if they don't, manually update driver software.
Proceed to step 7 above.
STUCK IN USB LOGO FIX
Hold power button for 10 seconds to make sure the device is completely turned off.
Hold volume up+power to boot to Droidboot mode.
Depending on what you intend to do, choose Recovery to boot to recovery mode, or Restart to reboot the device.
Some updates won't install no matter what. You did everything, automatic or manual flash, all you get is assert errors or the update simply won't appear. Or you modified your system (even just build.prop) and now you have to reflash to get rid of the update errors. That's where ADB sideloading comes in handy. This will allow you to flash a full firmware zip file so you can finally install that latest update. This also works for update firmware zips.
NOTICE
This may require advanced knowledge of how Device Manager and drivers installation work in Windows. This document will be edited to reflect any changes to the procedure, as well as provide links to the latest full/update firmware zips. The instructions assume you're using Windows 7/8/8.1 so it might be a bit different for previous or future Windows versions.
WARNING
Make sure you have the correct firmware for your device, especially for update firmware zips. You can't update TW with WW firmware.
Flashing instructions are not confirmed for Zenfone 5 LTE.
REQUIREMENTS
ASUS Zenfone 5/5 Lite/5 LTE
Windows-based PC (Windows XP, Vista, 7, 8, 8.1, 10)
ADB, fastboot and drivers installer 1.0.32 for Lollipop firmware
Full/update firmware zip (see links below)
USB debugging enabled
DOWNLOAD LINKS
Full firmware zip for ASUS Zenfone 5 A501CG/ASUS_T00J
3.23.40.78 WW [Lollipop 5.0] - Release notes
2.22.40.54 WW MR11.2 [KitKat to Lollipop bridge manual OTA, required for Lollipop update] - Release notes
Full firmware zip for Zenfone 5 Lite A502CG/ASUS_T00K
2.21.40.61 MR2.0 WW [KitKat 4.4.2] - Release notes
Full firmware zip for Zenfone 5 LTE A500KL/ASUS_T00P
12.4.5.50 WW [Lollipop 5.0] - Release notes
INSTRUCTIONS
Install ADB, fastboot and drivers using instructions in the link above.
Connect your Zenfone 5 to your PC and turn on USB debugging. The drivers should install automatically, if they don't, you have to manually update driver software in Device Manager.
Browse to the folder where you saved your full/update firmware zip, Shift+right-click, then click "Open command window here".
On the command prompt that opens, enter without quotes: "adb reboot bootloader".
The device should reboot to Droidboot mode, and drivers should install automatically, if they don't, manually update driver software.
Scroll to the "Recovery" entry on Droidboot using the volume buttons, then select using the power button. The device should reboot to recovery mode.
On the "No command" screen, follow the steps here if you're on KitKat, or here if you're on Lollipop. Select "Apply update from adb".
On the command prompt, enter without quotes: "adb sideload filename.zip" (example: adb sideload UL-ASUS_T00F-WW-3.23.40.60-user.zip). Wait for the transfer to finish.
After the transfer, your device should detect a firmware update and start to flash. Watch out for any errors.
If the flashing is successful, do a factory reset (for stability purposes).
If you get stuck in the USB logo (flash mode) screen, proceed to the fix instructions below.
You can now try an automatic or manual flash of the latest firmware, either using this method or via the device.
INSTRUCTIONS FOR FIXING BOOTLOOP
Download full/update firmware zip, and extract a copy of the recovery.img from the zip file. Keep both files in one folder.
Install ADB, fastboot and drivers using instructions in the link above.
Hold power button for 10 seconds to make sure the device is completely turned off.
Hold volume up+power to boot to Droidboot mode, and drivers should install automatically, if they don't, manually update driver software.
Proceed to step 7 above.
STUCK IN USB LOGO FIX
Hold power button for 10 seconds to make sure the device is completely turned off.
Hold volume up+power to boot to Droidboot mode.
Depending on what you intend to do, choose Recovery to boot to recovery mode, or Restart to reboot the device.