I attach some screens:
This is what appends if I try to update firmware as soon as the lamp is connected. Starts from +1%, jumps to -1% and then stops asking to retry.
Next screens show from both apps that the lamp is correctly added but offline
This last one shows that the lamp is seen connected to my WLAN by my router.
I've tried with both the app locations either on mainland china and US but there wasn't any difference.