It seems deliberate as if to dissuade.
And no, simply flashing the card wouldn't give me the fix I need. It would be in the .1.0 network after flashing the card unless you have an idea how to reset the 192.168.1.99 to another subnet on the card before it goes in the machine.
So, no. Holding the reset for 90 seconds brings it to that, 192.168.1.99, state.
The S5's wake up to DHCP so subnets are not a problem. But water cooled has lower temps than hard fan like the S5.
My C1 image with DHCP setting
www.perearstike.ee/C1/C1first.zipYou can use it.
Thanks for the offer but I solved it with a simple reset, albeit if holding the reset button in for 90 seconds is simple. That's what I mentioned in the previous post as, at least for me, better than taking the cover off, removing the microSD card and dd'ing an image to the card then putting the card back, cover on, and returning the miner to its installation.
The hard reset fixed the failure to accept ssh logins.
I like your idea of saving an image having DHCP set. Saving an image, an archived backup, that can be used on any C1 is a good idea. After wakeup on the subnet one could change the configuration to a static IP and unique miner ID.
When I fix the second C1 using the 90 second reset I'll save an archive copy after setting DHCP.
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Later I realized that a settings archive probably won't fix a ssh failure to login. Failure occurred when I copied the file addition to /sbin to the permanent record using cp -rf /etc/shadow /config/ and resetting restores the /config/ while a settings archive might not.