I have been using UIFlow and is very impressed by its simplicity. However, if I burn other sketches on it with Arduino IDE, the UIFlow along with downloaded apps will be replaced by the sketch.

Is it possible to have something like GRUB (https://www.gnu.org/software/grub/) so when M5Stack is booted up, it is possible to choose whether to run UIFlow or burned Arduino sketch. Not sure if this farfetched, but is something like this possible?

The place we are setting up is black colored theme and I am using the PIR Unit. Painting the PIR Unit black is not an issue, but it got the White Fresnel Lens (the white dome thing). So I would like to replace it with a black one.

I have been trying to open up the PIR Unit, but I have a bit of difficulty disassembling it. I am afraid that if I apply too much force, it will break. Or is it ok to apply more force until the whole thing is split in half? Is there anything holding inside? Must it be open in a special way?