@Jon67 

Good day.

Thank you very much for your time and patience.

Did the smart light bulb stop working just after the firmware update?

And Is there any abnormal behavior on the smart blub during firmware upgrade?

 Normally, during the firmware update, it is not allowed to unplug or power off the smart light bulb, or cut off the internet connection from the home router;

And if there is no obvious misbehavior, and only 1 of 6 is broken under firmware upgrade;

There is a large possibility that the product itself might have some issue;

Thank you very much.

@Brook When does a firmware update occur?

@Jon67 

Sorry, I might mistake some details.

I thought it  won't illuminate because of the firmware upgrade;

But apparently, it was broken for no reason but it is not a known issue.

For the special tips of usage, there is no something you need to pay a lot of attention, just do not over-use it in case it generate too much heat; (while since I mentioned firmware update before, you would automatically get the notification when there is a new firmware available and you could decide to update it or not; and if you want to update, ,make sure the smartphone has a stable wireless connection from the home router and did not turn off the smart bulb during firmware update;)

Thank you very much for your kind reply.