Has anyone else done the suggested upgrade?
Sadly I'm on my way to work, GRR so I'll be offline on two miners for ten hours!
Suggestions on what to try/do when I get home?
Power never cycled, and they did the reboot countdown properly.
I have 36 sp20 in my home and i got same problem when one of them restarted (Not often).
Sometime, sp20 can not get the ip address from router(tp-link,DHCP). Moreover, myminer.io doesn't work properly to display up-to-date sp20's ip address. (I need go in router and check which ip address is allocated to SP20).
Reboot the router and miner (just the one never came back) may help.
I got them back, took a few reboots and shut downs.
I disabled DHCP for that reason, Set my ip's. but yeah I wish myminer.io gave better details.