Betafpv ELRS Flat antenna receiver bricked(help wanted)

Hi guys. Help wanted!!!

Got issue with my new Betafpv ELRS flat antenna nano receiver, any help are appreciated.
---
---
# Background:

Wire it up and flash successfully the v2.2 offical firmware through WIFI to match my TX.
After successful flash, the receiver bricked with slow single short LED flash and no other response
(No binding, No WIFI, No flash firmware)

# Current symptom:
## 1. Slow single short LED flash after power up. Can't bind, flash, wifi etc.

https://user-images.githubusercontent.com/14341558/155278344-796e7353-ac8e-43bb-be09-3ae9ecc3df7c.mp4

Flash through UART will fail with ESP8266 timeout exception

## 2. Short firmware upgrade pad and GND. Power up with Sold blue LED.
Short two pad and power up. Receiver got solid LED. Can flash through `UART` only (BFpassthrough with ESP8266 exception, WIFI can't enable, UART flash works)

Tried Offical `v2.2` `v2.0` firmware, Betafpv `v2.0` `v1.1.0` forked firmware. All can flash successfully with above mentioned `UART` method. But issue remains.

Power cycle three times won't help either. slow led flash no response remain.

At this stage, I was wonder whether this is a hardware issue.
If anyone can explain the meaning of `slow short single LED flash` means. That would be appreciated as well.

Thank you
Regards