This is the official page from which you can Download HTC Desire 816T Stock Firmware ROM (flash file) package on your Computer.
The firmware package comes as a compressed file (zip file) which contains Flash File, Flash Tool, USB Driver and How-to Flash Manual.
HTC Desire 816T Stock Firmware ROM (flash file)
The HTC Stock ROM will help you to downgrade or update your HTC Device. It also helps you to fix the device if it is having any Software related issue, Bootloop issue, IMEI related issue or facing WiFi related issue.
Package Name: HTC_Desire_816T_Sense_6.0_2.06.1400.3_OTA.zip
Package Size: 654 MB
How-to Flash: Copy update.zip file to phone SD memory and flash it from the recovery mode.
How to Flash HTC Desire 816T Stock ROM
Step 1: Download and upzip the firmware package on your computer.
Step 2: After unzipping the Firmware package, you will get the Firmware (ROM), Driver, How-to Flash Manual.
Step 3: Install the given HTC USB Driver on your computer. Once installation is completed, connect your device to the computer.
Step 4: Open the Firmware Folder and copy the update.zip file to the phone sd memory.
Step 5: Power Off your Device.
Step 6: Boot your device into the Recovery Mode.
Step 7: From recovery mode, locate the update.zip file and flash it. Once Flashing process is completed, restart your device.
[*] HTC Driver: If you want to download the latest version of HTC USB Driver, then head over to the HTC USB Driver Download Page.
[*] Take a Backup: Flashing the above Firmware will delete the personal data from the device and you wont be able to recover it in anyway. Therefore, we recommend you to take a backup of the personal data before flashing the above firmware.