Purchase new Tello and connect no problem, updated firmware and now it will not show up on my wifi network on my iPhone X.  Tello flashes yellow, have reset wifi 3 times with no luck.  Deleted and redownloaded app.

How about trying upgrading again with the method below ?
Step 1 : Power off the drone first
Step 2 : Hold the power button with power off for about  5 to 8S until the green led goes off. [ Gotta release it as soon as the green led turns off ]
Step 3:  Once successed, it would flashing red led.
Step 4:  Then connect Tello's wifi and redo firmware upgrade.

I have the same problem. Tried everything but cant see wifi Tello.

Dejan Filipovic Posted at 3-16 08:32
I have the same problem. Tried everything but cant see wifi Tello.

Hi Dejan, can you pilot the drone despite the black screen?  Have you tried another mobile phone?
If persists, we respectfully suggest you contact us at support@ryzerobotics.com for further assistance.
Have a fantastic day ahead.

Hola adquirí un dron Tello y no me puedo conectar a él y no deja de parpadear la luz roja y ya cargué la batería pero sin resultados ??