Guide - How to Upgrade ROM / Firmware on Android HTC One A9 (AT&T/Cricket).

Upgrade ROM / Firmware on Android HTC One A9. On this guide We will show you how to Upgrade ROM / Firmware on Android HTC One A9 Smartphone. Upgrading your android system will increase phone performance, patch any security hole, increase battery performance, and much more. If you are now have HTC One A9 you can following this guide to upgrade your device. HTC One A9 device Available released on 2015, September, this device is the smartphone with 5,0 Inchi wide AMOLED capacitive touchscreen, 16M colors, work on Android OS, v6.0 (Marshmallow), upgradable to v6.0.1 (Marshmallow) and supported with Quad-core 1.5 GHz Cortex-A53 & quad-core 1.2 GHz Cortex-A53 CPU, GPU Adreno 405, combined with 2 GB of RAM and 13 MP o n main camera, and 4 MP on secondary camera.

On this guide not available for Verizon Wireless Devices. However select Verizon Wireless devices can be updated using the HTC Sync Manager software. So you must download HTC Sync Manager software Here.

Prerequisite.

1. Download HTC One A9 ROM.

http://dl3.htc.com/application/RUU_HIA_AERO_UL_M60_SENSE7GP_ATT_Cingular_US_1.27.502.5.exe

2. ROM  Versions.

1.27.502.5

Whats new on this ROM.

On this ROM provides the following key enhancements:

1. Battery improvements.
2. Camera improvements

Guide to Upgrade ROM / Firmware on Android HTC One A9.

1. Make sure your device is HTC One A9.
2. Make sure you have fully battery charge or at least you have 80% of battery capacity.
3. Make sure your HTC One A9 device is connected to AT&T 4G/LTE or a stable Wi-Fi network
4. Make sure to confirm  that this software upgrade to 1.27.502.5 is a newer version than what is currently loaded on your HTC One A9 device.
5. If your software version is the same with this version, just cancel to proceed this guide.
6. To check your software version you can go to ;
• All apps > Settings > About and locate the Software information.
7. Then, if your software version is less then 1.27.502.5 you should proceed with this upgrade.
8. Installation.
• On Line Installation.
• When your HTC One A9 device goes On Line, you can download and install the update from the device.
• Go toHome screen then tap All apps , 
• Then tap Settings
• Tap AT&T software update.
• Then tap Check for updates.
• Now, tap Continue to download the update.
• If downloading the update using the mobile data network (not connected to Wi-Fi), you may be prompted with a data fee warning message. If this is acceptable, tap YES to start the upgrade process.
• The status of the download can be checked in the Notifications pull down.
• Once the download is complete, the user will be prompted to install from the Notifications pull d own. Tap the System update to begin the upgrade process.
• Tap OK to begin the update process to software version 1.27.502.5.
• Now your HTC One A9 device  will reboot and begin installation.  
• The process will take approximately 10 minutes.
• Once the system update is complete, tap OK to continue. 
• Attention: During upgrade process, your HTC One A9 device will reboot multiple times. (this is normal) and software upgrade will show on screen. So, Dont do this on your device;
• Remove charger.
• Switch off device by press power button for long time.
• If you did it, your device might damage.
• Manual system update.
• Use this method to upgrade HTC One A9 device will delete all data and information stored on this d evice. Make sure you backup all data before proceed this task.
• Download and save the HTC Oneâ„¢ ROM update to your PC.
• Then, Connect your  HTC One A9 device to your PC via the original USB cable.
• If the device is not recognized by the PC, ensure you have HTC Sync Manager installed and then disconnect and reconnect the device from the USB cable.
• Once the HTC One A9 device is properly recognized on the PC, locate the HTC Oneâ„¢ ROM Update that you downloaded. Double-click on the file to launch the system update wizard.
• Follow all of the system update wizard instructions shown on your PC.
• Once the update is complete, click Finish in the Wizard and the device will reboot.
• Once the HTC One A9 device reboots, the initial setup wizard will appear.
• After the initial setup process is complete, open Play Store and tap the Menu icon, then select My apps and ensur e all installed apps are updated.
• After initial setup and updating all apps, the device is ready for use.

Trouble shooting.

If the ROM update process fails to recognize the HTC One A9 device, close the wizard and then follow this step below;

1. From powered Off state device, Press and hod Volume Down + Power Button  to access download mode.
2. Then, connect the HTC One A9 device to the PC while in this state and attempt the ROM update again.
3. Once upgrade process finished, you can exit from download mode by using volume keys to navigate to reboot and press the Power button to confirm it.
4. Finish.