@wjcarpenter Standby voltage. the stick doesn't truly power off and there is always a small voltage present in the stick which is why the battery always runs out.
The voltage increasing with a cable plugged in is normal and thank you for pointing out this function.

@kenneth123 Just tried and logged in with no issues.

@Slarck You should always Erase first because of this. never just burn only.
Thats the reason for the big red erase button being there!

@yuyun2000 Did you Erase existing firmware first?

@jbruggem Your first post shows that

1. you haven't configured Arduino to configure code for the M5Stack Core2 which uses a different core and pin config to a base esp32.
2. The example you are using is not an M5Stack demo,
3. Arduino is missing Libraries.

All these errors point back to not have the M5Stack Core2 board type selected.

@Slarck My pleasure.
Alas Last years attempt failed as everyone was too busy and this year I'm in the process of replacing my workshop along with with other sheds But I will announce the 2025 version again in September. on all social media channels this year.

@jeremyn3 You need to follow the instructions on the CoreMP135 product page.

@Boomvalt Xcode is OSX's dev environment and is needed for some low level functions needed for hardware programming even if you are not directly using it.

@KC5JIM Disconnected usually means that UIFLOW2 has lost connection to the server.
Have you erased the old firmware before burning the latest updated version for UIFlow2 for the AWS?

@Boomvalt No must always erase first to remove the previous firmware and config.
Once the erase process is done then you will be asked to bind (you may need to erase the old Atom3 from UIFLOW2 account first) then you can burn a clean update.