I believe you are missing the "Limit" field, which should come between the upload type (0 for upload) and the flash offset. The doc contains a mistake in any case here because it states that Limit is one byte long but in fact it's a 4 byte unsigned int, much like offset. The limit field is ignored for uploads but it still needs to be there.
I will correct the documentation immediately.
Automatic shutdown on low battery happens after one minute. You can monitor the battery status every 10 seconds (for example) with
pivoyager status battery and initiate a shutdown when you get
low battery in the output.
The more I think about it, the more I think I prefer the wing direction. Although, it's not clear there is room for the connectors with mounting screws in place? An option might be a wider "base" board, like the screw terminal wing or TFT FeatherWing.
We had not thought about that. Good idea. We might give it a try.