I have 11x S20 sonoff sockets. 8 of them I have upgraded to firmware 1.6.0 from the ewelink software without a problem.
I have 3 devices that will not upgrade
1x S20 with 1.5.2 firmware
2x S20 with 1.5.5 firmware
I've tried power cycling them, restarting the app, restarting the phone etc several times. They have failed to upgrade several times.
It's wierd that 8 devices upgrade fine, but 3 don't so something must be different.
How do I debug this?