How to update VoLTE for ZD551KL?

Last Update : 2018/01/15

D551KL VoLTE issue fix is here.. Are you ZD551KL (Selfie) user? Do you have VoLTE not working issue on your device? Here is the fix..! WW_ZD551KL_21.40.0.2214 is the latest FOTA which has VoLTE issue fix. Note: If your device is on 21.40.0.2210 you can download 21.40.0.2214. If your device is on 21.40.0.2156 You can straigth download 21.40.0.2214 skipping 21.40.0.2210. Make sure your device runs only on .2214 in the end as this is the VolTE fix frmware. Users can upgrade firmware on phone by auto or manual update. *If you do not receive notices of firmware updates, please refer to: http://www.asus.com/support/FAQ/1010274 [url=]a[/url]. Auto Update Note: During update process, please charge your phone with AC adaptor or make sure the phone has at least 15% battery life. Tap "Check Update" in "Settings" -> "About" -> "System update" to check if the firmware is latest. If there is newer version available, please follow steps shown on screen to execute update. [img]http://www.asus.com/zentalk/data/attachment/forum/201506/06/220712z2t274arzj0aj42b.jpg.thumb.jpg[/img] b. Manual Update You can also go to ASUS official website to download newer firmware and instruction manual. Note: Please make sure the firmware SKU you download is conformed to what on your phone, eg., WW -> WW, CN -> CN, TW -> TW. Incorrect SKU will lead to update failure. You can not change the SKU from one to another, eg., WW -> TW, and also can not downgrade your firmware, eg., V2.20.40.13 -> V2.19.40.18. During update process, please charge your phone with AC adaptor or make sure the phone has at least 15% battery life. Steps for update: 1. Go to "Need Help?" page of ASUS official website http://www.asus.com/support to download ZIP file of firmware. Note: Double click the ZIP file after downloading is completed. If the content is another intact ZIP file (as shown in red on picture below), please upzip the file again. If the content is not an intact ZIP file (as shown in yellow), you do not have to do anything. Close the ZIP file after check. [img]http://www.asus.com/zentalk/data/attachment/forum/201506/06/220714cuflvwlz4lnfnf44.jpg.thumb.jpg[/img] 2. Connect your phone with PC via micro USB cable, and copy the ZIP file to the root directory of internal storage of phone. [img]http://www.asus.com/zentalk/data/attachment/forum/201506/06/220718myz0ftmbjz000jl4.jpg.thumb.jpg[/img] 3. Detach micro USB cable from the phone to make the notification for firmware update poped up on status bar. [img]http://www.asus.com/zentalk/data/attachment/forum/201506/06/220721tu00oz9u0obl3ulo.jpg.thumb.jpg[/img] 4. Tap "System Update File Detected..." and follow steps to update firmware. [img]http://www.asus.com/zentalk/data/attachment/forum/201506/06/220723df22fer00we0m4mj.jpg.thumb.jpg[img] Note: Steps or photos shown above may have variation by different models. For some upgraded versions that have great difference, e.g., from Jelly Bean (Android 4.3) to KitKat (Android 4.4), you may need to upgrade to a "bridge version" in advance to proceed. Please see picture below for example. [img]http://www.asus.com/zentalk/data/attachment/forum/201502/08/182156beuvelil4ekveib9.jpg.thumb.jpg[/img] We hope you issue gets resolved.