Why does HTC Desire 820 battery life very low?

Well it totally depends on your usage. Also, keep in mind that battery performance worsens as it gets old.

Why doesn’t my HTC Desire 820 support USB OTG though company says it has support usb otg?

Hi TapanShah. Which USB OTG are you using? Try using a different, seems that the phone actually supports it but may be selective with the OTG device you use.

How to update HTC Desire 820Q when mobile is saying phone is up to date?

Well, it says up to date. You will have to wait for another update to come.

What to do when HTC Desire 820 3.5mm audio jack is not working?

Hi Chintan. It's best to directly contact HTC to get a quote on the repair cost. Tried looking for replacement parts online but failed to find any.

How much does it cost to replace HTC Desire 820 display?

Hi pritim. Found parts online that goes for $7.49. Check out this item from eBay: Link

What to do if HTC Desire 820 has gone in safe mode?

Hey Vinny. Simply restart your phone to exit safe mode.

What to do when SIM card with SIM tray gets stuck in HTC Desire 820?

Hi Anmol. I suggest that you take the phone to a nearby service center to avoid any further problems. Contact HTC to know the nearest one in your area.