Disabling internal voltage regulator on STM32F415 UFO target

The RTFM page on STM32F targets has a note about disabling internal regulator

By default the CW308 board attempts to provide power for these pins, but the voltage may not be high enough to cause the internal regulator to disable itself. In this case you can use the VADJ regulator to ensure the internal regulator is disabled.

How do I know when disabling of the internal regulator is achieved vs when it’s not? Tried to experiment with VADJ adjustments and looking at changes from differential probe, but I can’t tell the difference when it should happen (F415 seems much more noisy/jittery compared to other ARM chips).

I’ve read some threads on this forum referencing internal regulator like this one here that suggest that the STM32F415 UFO target board is designed in such way that it should be already be “out of the box built-in”? I.e. without using the VADJ network it should be fed “just right” to disable the internal regulator? (1.2 V input to VCAP but 3.3V to VDDA is right? why this way?)

Or in other words, what should I measure/check that I have set it up right?

Trial and error, e.g. whether voltage glitching works or not.