Hi Ben,
Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.
1)why is the function pin_mux.c::BOARD_InitPins() configuring USB0_VBUS since it should only be configured when using USB0 in device mode and the program actually configures USB0 as a host controller?
-- Thanks for your reporting, I'll contact to SDK team for checking it.
2) what is the purpose of configuring PIO4_9 (main.c) as GPIO output ? I don’t find any references to PI04_9 in the dev board manual. The comment refers to VBUS and I am trying to understand how it relates to USB0_VBUS.
-- The PIO4_9 is nothing with the USB0_VBUS pin, you can figure it out when reviewing the SCH of LPCXpresso54608 board.

Fig 1
Hope it helps.
Have a great day,
TIC
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