Hey there ShiMonononofu,
Sorry to hear about the consistent error message that you are getting, I'm sure it can be confusing, but I'm happy to look into this for you.
Are you using Nest provided USB cables as replacement or are you using third party cables? We always recommend to use Nest provided accessories to make sure that it meets the requirements.
I look forward to your response.
Hi there, ShiMonononofu.
I am glad to hear that you are using Nest accessories with your Nest Guard. I am sure it has been quite frustrating with it not functioning. I would love to figure this out together.
Please let me know if you need further assistance! I look forward to your response.