I upgraded to a C8 about a month or so after they were released. I transferred my C7 to the C8 with no issues.
I have a Zigbee custom device (TI2530 based) that will not pair with the C8. Symptoms are, absolutely no communication, the C8 just does not find my new device.
Two of the same based devices are currently running on the C8, however I've never had to pair them with the C8 they were carried over from the C7
Now I can't pair one of these new devices that had previously worked with the C7.
I would like to turn off my C8, power up the C7 which still has most of the current devices paired so I can test my custom device.
Now my question:
Will / could this confuse the devices so when I go back to the C8 they will have problems? There will be both Zigbee and Z-Wave devices.
I would reset the C7 and its radios, and then change the zigbee channel before attempting this.
I think you might be correct. However I was hoping in the event (hopefully never) my C8 fails the C7 would be easier to resurrect.
My alternative is to perform this test far away from my home. I think I'll first do this. Both devices are 5V so power is easy to obtain remotely.
Assuming the C8 keeps running for a while (and it's likely past any "bad luck/bad HW" period) you'd likely have too many differences since you moved to the C8 to fall back gracefully to the C7, which would have older hub FW, older apps, automations, devices/device setups, etc.
To resume using the C7 you'd probably need/want to restore a full cloud backup from the C8 to the C7 anyway. Z-wave would be fully restored on the C7. You'd have to re-join the Zigbee devices to the C7 but they should all fall into their automations on the C7 and you'd be up and running pretty quickly.
I was more concerned with the Z-Wave devices. Their numbers are larger and it seems like repairing them is more of a pain than Zigbee (when it works).
Oh and I don't have cloud backup.
You really should. Cheap as chips and will save you a lot of time/heartache if you have an issue w/your hub. You get a full restore of both Zigbee and Z-Wave devices from a cloud backup to a C8, and full restore of Z-Wave devices to a C7, so really worth it, IMHO, especially if you're more concerned w/Z-Wave. Z-Wave is more work to re-join w/out a cloud backup, requires full exclude before re-joining, and more complicated as you have to put Z-Wave devices back into existing automations. Even if you're using Swap Apps Device it will be a PITA.