Hi  @Wayne-TP 

Thanks for the comments.  It's not a WiFi thing unfortunately that I can validate for a few reasons:

1. On the same network v2 P100 devices update their firmware successfully
2. On the same network other Tapo devices including cameras all update their firmware fine
3. Prior to FW 1.4.9 arriving on the v1 P100 devices they updated the firmware successfully
4. To rule out the network I created a hotspot from my phone and connected one of the affected v1 P100 devices to the hotspot and it still fails to update the firmware

From my experience it feels like a bad firmware or similar blocking the download of new firmware.  But obviously I can't specifically prove that other than to say only by V1 P100 devices are impacted and all other Tapo devices on the same network are fine.

Is there a way to connect directly to a device and update the firmware directly rather than from the app?  I know they don't appear to present a webpage as such (certainly not on HTTP or HTTPS), but is there something where I can interact directly with the device?