MCUSR - BORF: Brown-out Reset Flag

Atmega328 Datasheet states: " Bit 2 – BORF: Brown-out Reset Flag
This bit is set if a Brown-out Reset occurs. The bit is reset by a Power-on Reset, or by writing a ‘0’ to it."
Well… How is Brown-Out flag reset on power on is ALWAYS after Brown-Out?? Chicken or egg thing?

How is this statement true?

Is it ever possible to have a Power-On flag without Brown-Out Flag (BOD enabled of course)

A BOR is not a POR. If it dips below BOD voltage, but not POR reset voltage, you will get BORF only. Of course, if you never cleared the old PORF flag, from the last power on, it would still be there…

I’m not sure if you can get PORF without BORF, but if you can, you’d get it with a very fast rising power supply, if you can get the supply rails up within the startup time? could test by rigging up a '328 in DIP on protoboard with just 0.1uF decoupling caps, and then connecting it to a 5v power supply with a beefy capacitor on the output such that the voltage very quickly reaches operating conditions?

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